Lithium-lanthanum-zirconium composite oxide solid electrolyte as well as preparation method and application thereof

Abstract

The invention discloses a lithium lanthanum zirconium composite oxide solid electrolyte and a preparation method and application thereof, the chemical general formula of the lithium lanthanum zirconium composite oxide solid electrolyte is Li7-aGabLa3-cCecZr2-dMeO12-fZf, M is a cation doped element, Z is an anion doped element, 0 < a < = 2, 0 < b < = 0.5, 0 < c < = 1.5, 0 < = d < = 1.5, 0 < = e < = 1.5, 0 < = f < = 0.5, and 0 < = f < = 0.5. According to the lithium lanthanum zirconium oxide solid electrolyte obtained by the preparation method, generation of holes in the electrolyte can be reduced, meanwhile, the density of the electrolyte is improved, and the interface impedance is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state battery electrolyte preparation, and particularly relates to a lithium lanthanum zirconium composite oxide solid electrolyte, a preparation method thereof, and an application thereof. Background Art

[0002] Since the commercialization of lithium batteries, due to their high energy density, cycle performance, good portability, and low self-discharge, and at the same time affected by the global energy crisis and the call for environmental protection, lithium batteries have become the fastest-growing chemical energy storage power source at present. The organic electrolyte used in traditional commercial lithium batteries gives lithium batteries a high ionic conductivity, with a small interfacial impedance and good wettability with the electrode, but it is prone to mechanical, thermal, and electrical abuse, and there are safety hazards. Side reactions in the electrolyte will corrode the electrode and form a solid electrolyte interphase, reducing the service life, and a lithium metal negative electrode cannot be used, and the energy density is limited. For solid-state lithium batteries, some of the solid electrolytes used have more stable structures and chemical properties, a wide electrochemical window, high safety, and good interfacial compatibility, and a lithium metal negative electrode can be used. Therefore, solid-state lithium batteries have a high energy density and can reach 500 Wh·kg -1 Above, it is expected to be used as a power source for vehicles and aircraft in the future, and the application prospect is broad. Solid electrolytes include inorganic solid electrolytes and polymer solid electrolytes. Among them, although inorganic solid electrolytes have inferior interfacial compatibility to polymer solid electrolytes, they have higher ionic conductivity, a wider electrochemical window, and better safety, and can be used to prepare all-solid-state lithium batteries. Inorganic solid electrolytes can be mainly divided into: oxide type, sulfide type, and halide type. Oxide-type solid electrolytes represented by lithium lanthanum zirconium composite oxide electrolytes have a wide electrochemical window, good stability, and high ionic conductivity, and have good comprehensive performance. Lithium lanthanum zirconium composite oxide solid electrolytes usually require a relatively high temperature for solid-phase reaction synthesis and sintering into ceramics. And some lithium lanthanum zirconium composite oxide solid electrolytes are prone to generate pores inside the ceramics due to reasons such as sintering activity differences and chemical reactions at high temperatures, which is also a common phenomenon in solid oxide electrolyte ceramics. The pores in the electrolyte will increase the interfacial impedance, reduce the ceramic density, increase the battery internal resistance, increase the overpotential during the charge and discharge process of the battery, induce the deposition of dead lithium, and deteriorate the electrochemical performance of the assembled battery. Summary of the Invention

[0003] (1) Object of the Invention

[0004] The object of the present invention is to provide a lithium lanthanum zirconium composite oxide solid electrolyte, a preparation method thereof, and an application thereof. The lithium lanthanum zirconium oxide solid electrolyte obtained by the preparation method of the present invention can reduce the generation of pores inside the electrolyte, improve the density, reduce the interfacial impedance, enhance the ability of the electrolyte to resist the growth of lithium filaments, and show excellent lithium compatibility and cycle stability when applied to solid-state batteries.

[0005] (2) Technical solution

[0006] To solve the above problems, a first aspect of the present invention provides a lithium lanthanum zirconium composite oxide solid electrolyte, and the chemical general formula of the lithium lanthanum zirconium composite oxide solid electrolyte is Li 7-a Ga b La 3-c Ce c Zr 2-d M e O 12-f Z f , where M is a cation doping element, Z is an anion doping element, 0 < a ≤ 2, 0 < b ≤ 0.5, 0 < c ≤ 1.5, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, 0 ≤ f ≤ 0.5, 0 ≤ f ≤ 0.5.

[0007] Furthermore, in the lithium lanthanum zirconium composite oxide solid electrolyte, the content ratio of gallium to cerium is: 0.3 ≤ b / c ≤ 20, preferably 3 ≤ b / c ≤ 10.

[0008] Furthermore, the M includes at least one of cations Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W, P, In and rare earth elements, and the rare earth elements do not include La and Ce.

[0009] Furthermore, the Z includes at least one of anions S, F, Cl, Br and I.

[0010] Furthermore, the density of the lithium lanthanum zirconium composite oxide all-solid electrolyte ≥ 96%, measured by the Archimedes drainage method.

[0011] Furthermore, the cross-sectional micrograph of the lithium lanthanum zirconium composite oxide all-solid electrolyte is taken by a scanning electron microscope, and then the number of pores inside the electrolyte is measured and statistically obtained by Image J software ≤ 0.05 pores / μm 2 , and the average pore diameter inside the electrolyte ≤ 1.2 μm.

[0012] Furthermore, the molar content of the M does not exceed 8% of the total molar content of the solid electrolyte components, and the molar content of the Z does not exceed 3% of the total molar content of the solid electrolyte components.

[0013] A second aspect of the present invention provides a preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte as described in any one of the above descriptions, including the following steps:

[0014] S1. Compound lithium compound, gallium compound, lanthanum compound, cerium compound, zirconium compound, M compound and Z compound according to a preset stoichiometric ratio to obtain a mixed precursor; the compounding treatment includes physical treatment or chemical treatment;

[0015] S2. Calcinate, ball mill, dry and classify the mixed precursor to obtain a lithium lanthanum zirconium composite oxide solid electrolyte powder, which is one kind of lithium lanthanum zirconium composite oxide solid electrolyte.

[0016] Further, the method further includes S3: Process the lithium lanthanum zirconium composite oxide solid electrolyte powder obtained in S2 to obtain any one of a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet, film and tape.

[0017] Further, the mixed precursor includes a first mixed precursor and a second mixed precursor, the first mixed precursor is prepared by physical treatment, and the second mixed precursor is prepared by chemical treatment.

[0018] Further, the physical treatment in S1 includes: adding lithium compound, gallium compound, lanthanum compound, cerium compound, zirconium compound, M compound and Z compound according to a preset stoichiometric ratio into a dispersion medium for ball milling and mixing, and drying to obtain a first mixed precursor;

[0019] Further, the chemical treatment in S1 includes: carrying out a precipitation reaction on the solutions of gallium compound, lanthanum compound, cerium compound, zirconium compound and a part of the precipitable M compound according to a preset stoichiometric ratio, filtering and washing to obtain a precipitate, and then mixing the precipitate with lithium compound, the remaining non-precipitable M compound and Z compound evenly according to a preset stoichiometric ratio to obtain a second mixed precursor. In the chemical treatment, the M compound includes a co-precipitable M compound and a non-co-precipitable M compound.

[0020] Further, in the physical treatment, the ball milling speed is controlled at 200 - 800 rpm, the ball milling time is 1 - 24 h, the drying temperature is 50 - 200 °C, and the drying time is 4 - 24 h.

[0021] Further, in the chemical treatment, the pH value of the precipitation reaction is controlled at 9 - 12, and the precipitation reaction temperature is 5 - 40 °C.

[0022] Further, in step S2, the calcination temperature is controlled at 600 - 1100 °C, and the calcination time is 30 min - 24 h.

[0023] Further, the calcination atmosphere in step S2 includes at least one of air, oxygen, nitrogen, helium and argon.

[0024] Further, in the step S3, the processing temperature is 900-1350 °C, and the processing time is 30 min-24 h.

[0025] The third aspect of the present invention provides an application of the lithium lanthanum zirconium composite oxide solid electrolyte as described in any one of the above descriptions or the lithium lanthanum zirconium composite oxide solid electrolyte prepared by the preparation method as described in any one of the above descriptions in all-solid-state lithium metal or lithium-ion batteries, semi-solid-state lithium-ion batteries, and lithium-air batteries.

[0026] (III) Beneficial effects

[0027] The above technical solutions of the present invention have the following beneficial technical effects: The present invention provides a lithium lanthanum zirconium composite oxide solid electrolyte, a preparation method thereof, and an application thereof. The preparation method adopts a new material component design of lithium, gallium, lanthanum, cerium, zirconium, and doping elements M and Z, and physically or chemically processes lithium compounds, gallium compounds, lanthanum compounds, cerium compounds, zirconium compounds, M compounds, and Z compounds according to a preset stoichiometric ratio. The physical treatment adopts a solid-phase method, and the chemical treatment adopts a co-precipitation method. Then, the mixed precursor is calcined, ball-milled, dried, and classified to obtain a lithium lanthanum zirconium composite oxide solid electrolyte powder; finally, the lithium lanthanum zirconium composite oxide solid electrolyte powder is formed and then subjected to high-temperature treatment to obtain a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet, film, and tape. The gallium-containing lithium lanthanum zirconium composite oxide electrolyte is prone to disproportionation reaction to release oxygen during high-temperature treatment (Reaction formula 1), while cerium oxide has the ability to store and release oxygen. The addition of cerium can inhibit the disproportionation reaction of the dissolved gallium oxide in the electrolyte to release oxygen during high-temperature heat treatment (Reaction formula 2), reduce the generation of pores inside the electrolyte, and can also fill the grain boundaries as a second phase to connect the crystal grains and limit the abnormal growth of the grains. The high-valent cerium in the electrolyte lattice can also inhibit Li + from being reduced to dead lithium during the lattice lithium pathway transmission process, thereby reducing the deposition of dead lithium inside the electrolyte and the growth of lithium filaments. The chemical general formula of the prepared solid electrolyte is Li 7-a Ga b La 3-c Ce c Zr 2-d M e O 12-f Z f , where 0 < a ≤ 2, 0 < b ≤ 0.5, 0 < c ≤ 1.5, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, 0 ≤ f ≤ 0.5, 0 ≤ f ≤ 0.5. This electrolyte can improve the density after heat treatment, the density ≥ 96%, and the number of pores ≤ 0.05 pieces / μm 2, the average pore diameter inside the electrolyte ≤ 1.2 μm. This electrolyte has a high lithium-ion conductivity second only to sulfide solid electrolytes, good structural and chemical stability, high safety, environmental friendliness, strong ability to resist lithium filament growth, and the assembled battery has excellent comprehensive performance. The preparation method used has a simple process, is economically environmentally friendly, is easy to prepare on a large scale, has strong universality, and can also be extended to the preparation of other new lithium-ion solid electrolytes. This composite oxide solid electrolyte has a high density, high ionic conductivity, low ionic migration activation energy, good crystal structure and chemical stability, and has excellent cycling performance after assembling a solid-state battery. It can be used in fields such as lithium-metal batteries, lithium-ion batteries, and lithium-air batteries. The respective reaction formulas are shown as follows:

[0028] Brief Description of the Drawings

[0029] Figure 1 is the cross-sectional morphology diagram of the electrolyte ceramic in Example 1 of the present invention;

[0030] Figure 2 is the cross-sectional morphology diagram of the electrolyte ceramic in Comparative Example 1;

[0031] Figure 3 is the XRD diagram of the electrolyte in Example 1 of the present invention;

[0032] Figure 4 is the XRD diagram of the electrolyte in Comparative Example 1;

[0033] Figure 5 is the electrochemical performance diagram of the electrolyte in Example 1 of the present invention;

[0034] Figure 6 is the electrochemical performance diagram of the electrolyte in Comparative Example 1. Detailed Embodiments

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0036] The first aspect of the present invention provides a lithium lanthanum zirconium composite oxide solid electrolyte with a chemical general formula of Li 7- a Ga b La 3-c Ce c Zr 2-d M e O 12-f Z f, where M is a cation doping element, Z is an anion doping element, 0 < a ≤ 2, 0 < b ≤ 0.5, 0 < c ≤ 1.5, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, 0 ≤ f ≤ 0.5, 0 ≤ f ≤ 0.5, and the lithium lanthanum zirconium composite oxide solid electrolyte has a garnet cubic phase structure. The density of the lithium lanthanum zirconium composite oxide all-solid electrolyte is ≥ 96%. The number of pores in the lithium lanthanum zirconium composite oxide all-solid electrolyte is ≤ 0.05 pores / μm 2 , the average pore diameter is ≤ 1.2 μm, and the content ratio of gallium to cerium is: 0.3 ≤ b / c ≤ 20.

[0037] Furthermore, M includes at least one of cations Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W, P, In and rare earth elements, and the rare earth elements do not include La and Ce. Compounds of M include at least one of its oxides, hydroxides, nitrates, carbonates, phosphates, sulfates, acetates and citrates, and preferably, at least one of its oxides, hydroxides, nitrates and carbonates. The molar content of M does not exceed 8% of the total molar content of the solid electrolyte components.

[0038] Z includes at least one of anions S, F, Cl, Br and I, and compounds of the doping element Z include at least one of lithium, lanthanum, cerium, gallium, zirconium, fluorides, fluoroxides, chlorides, hypochlorites, chlorates, perchlorates, bromides, hypobromites, lithium bromate, lithium perbromate, lithium iodide, lithium hypoiodite, lithium iodate, lithium periodate, lithium sulfide and lithium hydrosulfide. The molar content of Z does not exceed 3% of the total molar content of the solid electrolyte components.

[0039] The second aspect of the present invention provides a preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte as described in any one of the above descriptions, and the preparation method includes:

[0040] S1. Compounds of lithium, gallium, lanthanum, cerium, zirconium, M compound and Z compound are compounded according to a preset stoichiometric ratio to obtain a mixed precursor; the compounding process includes physical treatment or chemical treatment. The physical treatment adopts the solid-phase method. Specifically, the physical treatment includes: adding compounds of lithium, gallium, lanthanum, cerium, zirconium, M compound and Z compound according to a preset stoichiometric ratio into a dispersion medium for ball milling and mixing, and then drying to obtain a first mixed precursor. The mixed precursor includes a first mixed precursor and a second mixed precursor, and the second mixed precursor is prepared by chemical treatment. In the physical treatment, if the ball milling speed is too low and the time is insufficient, the composition of the first mixed precursor is uneven; if the ball milling speed is too high and the time is too long, the Zr content and impurity content of the first mixed precursor are likely to increase. Therefore, the ball milling speed is controlled at 200 - 800 rpm and the ball milling time is 1 - 24 h.

[0041] The chemical treatment adopts the co-precipitation method. In the chemical treatment, the M compound includes a co-precipitable M compound and a non-co-precipitable M compound. Specifically, the chemical treatment includes: carrying out a precipitation reaction on the solutions corresponding to the compounds of gallium, lanthanum, cerium, zirconium and the co-precipitable M compound according to a preset stoichiometric ratio to obtain a precipitate, and then ball milling and mixing the precipitate with the compounds of lithium, the remaining non-co-precipitable M compound and the Z compound according to a preset stoichiometric ratio, and drying to obtain a second mixed precursor. The ball milling dispersion medium selected during the ball milling process includes at least one of air, oxygen, nitrogen, argon, helium, methanol, acetonitrile, ethanol, propanol, isopropanol, butanol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, acetone, butanone, toluene, xylene, methyl ethyl ketone, dimethyl sulfoxide, tetrahydrofuran, dioxane, ethyl acetate, methyl formate, chloroform, dimethyl carbonate, diethyl carbonate, acetic acid, acrylic acid, chloroacetic acid, ethylene glycol, glycerol, water, and a glycerol and water complex. Preferred ball milling dispersion media include at least one of air, oxygen, nitrogen, acetonitrile, ethanol, propanol, isopropanol, butanol, N,N-dimethylformamide and water. The precipitating agent used in the precipitation reaction during the chemical treatment process includes at least one of ammonia water, ammonium carbonate, ammonium bicarbonate, sodium hydroxide, sodium carbonate and sodium bicarbonate. In the chemical treatment, the pH value of the precipitation reaction is controlled at 9 - 12, and the precipitation reaction temperature is 5 - 40 °C. In the chemical treatment, after calculation, the pH value for complete precipitation of La 3+ is > 9, and for La 3+ and Zr 4+The pH values for complete precipitation vary significantly. To make the composition of the second mixed precursor more uniform, the pH value during the precipitation reaction is controlled at 9 - 12, and the precipitation reaction temperature is 5 - 40 °C. Meanwhile, during the physical treatment or chemical treatment process, the drying temperature is controlled at 50 - 200 °C, preferably 60 - 100 °C, and the drying time is 4 - 24 h, preferably 6 - 16 h.

[0042] Wherein the lithium compound includes at least one of lithium oxide, hydroxide, nitrate, and carbonate. The dosage of the lithium compound is 100 - 120 mol% of the theoretical stoichiometric amount.

[0043] The gallium compound, lanthanum compound, cerium compound, and zirconium compound respectively include at least one of the corresponding oxide, hydroxide, nitrate, carbonate, phosphate, sulfate, acetate, and citrate of their respective elements. Preferably, they include at least one of the corresponding oxide, hydroxide, nitrate, and carbonate of their respective elements.

[0044] The M includes at least one of the cations Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W, P, In, and rare earth elements, and the rare earth elements do not include La and Ce. The compound of M includes at least one of its oxide, hydroxide, nitrate, carbonate, phosphate, sulfate, acetate, and citrate. Preferably, it includes at least one of its oxide, hydroxide, nitrate, and carbonate. The molar content of M does not exceed 8% of the total molar content of the solid electrolyte components.

[0045] The Z includes at least one of the anions S, F, Cl, Br, and I. The compound of the doping element Z includes at least one of lithium, lanthanum, cerium, gallium, zirconium, M fluoride, fluoroxide, chloride, hypochlorite, chlorate, perchlorate, bromide, hypobromite, lithium bromate, lithium perbromate, lithium iodide, lithium hypoiodite, lithium iodate, lithium periodate, lithium sulfide, and lithium hydrosulfide. The molar content of Z does not exceed 3% of the total molar content of the solid electrolyte components.

[0046] S2, After calcining, ball - milling, drying, and classifying the mixed precursor, a lithium lanthanum zirconium composite oxide solid electrolyte powder is obtained. In the S2 step, the calcination temperature is controlled at 600 - 1100 °C, preferably 800 - 1000 °C, and the calcination time is 30 min - 24 h, preferably 4 - 12 h. The calcination atmosphere includes at least one of air, oxygen, nitrogen, helium, and argon. The lithium lanthanum zirconium composite oxide solid electrolyte is any one of a lithium lanthanum zirconium composite oxide solid electrolyte powder, ceramic sheet, membrane, and tape.

[0047] S3. Process the lithium lanthanum zirconium composite oxide solid electrolyte powder obtained in S2 to obtain any one of a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet, film, and tape. In the S3 step, the processing temperature is 900 - 1350 °C, preferably 1000 - 1250 °C, and the processing time is 30 min - 24 h, preferably 3 h - 12 h. The atmosphere required for processing includes at least one of air, oxygen, nitrogen, helium, and argon.

[0048] The third aspect of the present invention provides the application of the lithium lanthanum zirconium composite oxide solid electrolyte as described in any one of the above descriptions or the lithium lanthanum zirconium composite oxide solid electrolyte obtained by the preparation method as described in any one of the above descriptions in all-solid-state lithium metal or lithium-ion batteries, semi-solid-state lithium-ion batteries, and lithium-air batteries.

[0049] The present invention will be further described below through specific examples.

[0050] Example 1

[0051] Weigh Li2CO3, La2O3, ZrO2, Ga2O3, CeO2, and Nb2O5 according to

[0052] Li 6.05 Ga 0.25 La 2.9 Ce 0.1 Zr 1.9 Nb 0.1 O 12 the stoichiometric ratio and place them in a ball mill jar for ball milling and mixing. The Ga:Ce ratio is 2.5 (b / c is 2.5, and the same applies hereinafter). The ball milling dispersion medium uses isopropanol. The solid content of the powder and the dispersion medium slurry is 25%. The ball milling speed is 500 rpm, and the ball milling time is 12 h. Dry the mixed slurry at 80 °C for 12 h and then sieve it to obtain the first mixed precursor. After calcining the first mixed precursor in an air atmosphere at 740 °C for 5 h (the calcining atmosphere for Examples 2 - 10 is air), raise the temperature to 900 °C and calcine for 6 h with a heating rate of 5 °C / min. Then cool it to room temperature with the furnace. After refining the particle size by ball milling at 500 rpm for 8 h, dry and sieve it to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. Keep the green compact at 1280 °C for 30 min to obtain a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The lithium lanthanum zirconium composite oxide solid electrolyte has a garnet cubic phase structure, about 0.023 pores / μm 2 , the average pore diameter inside the electrolyte is 1.1 μm, the relative density is 96.2%, and the ionic conductivity at room temperature is 8.57×10 -4S / cm, the interfacial impedance of the assembled lithium symmetric battery is 94.8 Ω, using 0.2 mA cm 2 The current density was used for constant current charge and discharge test of cycle performance, and it could be stably cycled for 1860 h. The sample morphology, structure and electrochemical performance in Example 1 are shown in Figure 1 , Figure 3 and Figure 5 . Figure 1 is the cross-sectional morphology of the electrolyte, and almost no pores are visible. Figure 3 is the electrolyte structure, which is a cubic garnet structure. Figure 5 is the electrochemical performance. The assembled lithium symmetric battery was stably cycled for more than 1860 h at 0.2 mA cm -2 .

[0053] Comparative Example 1:

[0054] Li2CO3, La2O3, ZrO2, Ga2O3 and Nb2O5 were weighed according to the stoichiometric ratio of Li 6.05 Ga 0.25 La3Zr 1.9 Nb 0.1 O 12 and placed in a ball mill jar for ball milling and mixing. Isopropanol was used as the ball milling dispersion medium. The solid content of the powder and the dispersion medium slurry was 25%, the ball milling speed was 500 rpm, and the ball milling time was 12 h. The mixed slurry was dried at 80 °C for 12 h and then sieved to obtain the first mixed precursor. The first mixed precursor was calcined in air atmosphere at 740 °C for 5 h, then heated to 900 °C and calcined for 6 h, with a heating rate of 5 °C / min. Subsequently, it was cooled to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, it was dried and sieved to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder was formed by isostatic pressing at 200 MPa and kept under pressure for 5 min to obtain a green compact. The green compact was kept at 1280 °C for 30 min to obtain a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The lithium lanthanum zirconium composite oxide solid electrolyte has a garnet cubic phase structure, and the ceramic pores are about 0.18 pieces / μm 2 , the average pore diameter inside the electrolyte is 2.4 μm, the density is 93.6%, and the ionic conductivity at room temperature is 8.78×10 -4 S / cm. The interfacial impedance of the assembled lithium symmetric battery is 480 Ω, using 0.2 mA cm 2 The current density was used for constant current charge and discharge test of cycle performance, and it could be stably cycled for 445 h. The sample morphology, structure and electrochemical performance in Comparative Example 1 are shown in Figure 2 , Figure 4 and Figure 6 . It can be seen from the cross-sectional morphology of the electrolyte in Figure 2 that there are a large number of pores. Figure 4 The electrolyte structure is also a cubic garnet structure. InFigure 6 In the electrochemical performance diagram, the assembled lithium symmetric battery short-circuited after cycling for about 445 h at 0.2 mA cm -2 The sample morphology, structure and electrochemical performance in Comparative Example 1 are shown in Figure 2 , Figure 4 and Figure 6 . Figure 2 is the cross-sectional morphology of the electrolyte, and a large number of pores can be seen. Figure 4 is the electrolyte structure, which is a cubic garnet structure. Figure 6 is the electrochemical performance. The assembled lithium symmetric battery short-circuited after cycling for about 445 h at 0.2 mA cm -2 .

[0055] Example 2

[0056] Mix the La(NO3)3 solution, ZrO(NO3)2 solution, Ga(NO3)3 solution and Ce(NO3)3 solution according to the stoichiometric ratio of Li 5.5 Ga 0.25 La 2.9 Ce 0.1 Zr 1.35 Nb 0.65 O 12 to prepare the feed solution. The GaCe ratio is 2.5. Use ammonia water as the precipitant to carry out coprecipitation with the feed solution (precipitate). The pH during the precipitation reaction process is 9.6 - 10.9. After the precipitate precursor is filtered and washed, it is dried at 200 °C for 12 h, and then ball-milled and mixed with stoichiometric lithium carbonate and stoichiometric niobium oxide (the part of ball-milling and mixing after precipitation is M compounds that cannot carry out coprecipitation, and the same applies to subsequent examples). The ball-milling dispersion medium is isopropanol, the solid content is 25%, the ball-milling speed is 500 rpm, and the ball-milling time is 12 h. After drying the mixed slurry, it is screened to obtain the second mixed precursor. The second mixed precursor is calcined at 600 °C for 4 h, 740 °C for 5 h, and then heated to 850 °C for 6 h in an air atmosphere, with a heating rate of 5 °C / min, and then cooled to room temperature with the furnace. After ball-milling at 500 rpm for 8 h to refine the particle size, it is dried and screened to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. The green compact is sintered at 1250 °C for 60 min to obtain a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet, which has a garnet cubic phase structure. The ionic conductivity at room temperature is measured to be 1.71×10 -4 S / cm, the ceramic pores are about 0.024 per μm 2 , the average pore diameter inside the electrolyte is 0.9 μm, the relative density is 96.9%, the lithium interface impedance after assembling the lithium symmetric battery is 1174.8 Ω, and using 0.2 mAcm 2The ability of the electrolyte to resist the growth of lithium filaments was tested by constant current charge and discharge at a current density, and it could be stably cycled for 954 h.

[0057] Example 3

[0058] Li2CO3, La2O3, ZrO2, Ga2O3, Ta2O5 and CeO2 were weighed according to the stoichiometric ratio of Li 6.05 Ga 0.2 La 2.95 Ce 0.05 Zr 1.8 Ta 0.2 O 12 and placed in a ball milling jar for ball milling and mixing. The Ga:Ce ratio was 4. Isopropyl alcohol was used as the ball milling dispersion medium, the solid content was 25%, the ball milling speed was 500 rpm, and the ball milling time was 12 h. After drying and sieving the mixed slurry, the first mixed precursor was obtained. After calcining the first mixed precursor at 740 °C for 5 h in an air atmosphere, it was heated to 900 °C and calcined for 6 h at a heating rate of 5 °C / min. Then it was cooled to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, it was dried and sieved to obtain a lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder was formed by isostatic pressing at 200 MPa and kept under pressure for 5 min to obtain a green compact. The green compact was sintered at 1280 °C for 30 min to obtain a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The ionic conductivity at room temperature was tested to be 6.55×10 -4 S / cm, the ceramic pores were about 0.038 pores / μm 2 , the average pore diameter inside the electrolyte was 0.62 μm, the density was 96.0%, the lithium interface impedance was 101.8 Ω after assembling a lithium symmetric battery, and the ability of the electrolyte to resist the growth of lithium filaments was tested by constant current charge and discharge at a current density of 0.2 mA / cm 2 and it could be stably cycled for 1794 h.

[0059] Example 4

[0060] La(NO3)3 solution, ZrO(NO3)2 solution, Ga(NO3)3 solution and Ce(NO3)3 solution were mixed according to the stoichiometric ratio of Li 6.05 Ga 0.2 La 2.95 Ce 0.05 Zr 1.8 Ta 0.2 O 12Prepare a stoichiometrically proportioned feed solution, and use ammonia water as a precipitant to carry out coprecipitation with the feed solution. The pH during the precipitation reaction process is 9.5 - 11.0. After filtering and washing the precipitation precursor by suction, dry it at 200 °C for 12 h. After drying, mix it by ball milling with stoichiometric lithium carbonate and stoichiometric tantalum oxide. The ball milling dispersion medium is isopropanol, the solid content is 25%, the ball milling speed is 500 rpm, and the ball milling time is 12 h. Dry the mixed slurry and then screen it to obtain the second mixed precursor. Calcinate the second mixed precursor in an air atmosphere at 600 °C for 4 h, at 740 °C for 5 h, then heat it up to 850 °C and calcinate for 6 h, with a heating rate of 5 °C / min, and then cool it to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, dry and screen it to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. Sinter the green compact at 1280 °C for 30 min to obtain the lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The ionic conductivity at room temperature is tested to be 6.37×10 -4 S / cm, and the ceramic pores are about 0.041 pores / μm 2 , the average pore diameter inside the electrolyte is 1.0 μm, the relative density is 97.2%, the lithium interface impedance is 114.8 Ω after assembling a lithium symmetric battery, and use 0.2 mAcm 2 The current density is used for constant current charge and discharge testing of the ability of the electrolyte to resist lithium filament growth, and it can be stably cycled for 1714 h.

[0061] Example 5

[0062] Weigh Li2CO3, La2O3, ZrO2, Ga2O3, CeO2 and Y2O3 according to the stoichiometric ratio of Li 6.15 Ga 0.25 La 2.8 Ce 0.1 Y 0.1 Zr2O 12 After weighing according to the stoichiometric ratio, place them in a ball milling tank and mix them by ball milling. The Ga:Ce ratio is 2.5. The ball milling dispersion medium is isopropanol, the solid content is 25%, the ball milling speed is 500 rpm, and the ball milling time is 12 h. Dry the mixed slurry and then screen it to obtain the first mixed precursor. Calcinate the first mixed precursor in an air atmosphere at 740 °C for 5 h, then heat it up to 900 °C and calcinate for 6 h, with a heating rate of 5 °C / min, and then cool it to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, dry and screen it to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. Sinter the green compact at 1260 °C for 40 min to obtain the lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The ionic conductivity at room temperature is tested to be 9.61×10 -4 S / cm, and the ceramic pores are about 0.026 pores / μm2 , the average pore diameter inside the electrolyte is 0.87 μm, the density is 96.5%, the interfacial impedance to lithium after assembling the lithium symmetric battery is 84.8 Ω, and a constant current charge-discharge test is carried out on the ability of the electrolyte to resist the growth of lithium filaments at a current density of 0.2 mA cm 2 , and it can be stably cycled for 1867 h.

[0063] Example 6

[0064] Prepare the feed solution according to the stoichiometric ratio of La(NO3)3 solution, ZrO(NO3)2 solution, Ga(NO3)3 solution, Y(NO3)3 solution and Ce(NO3)3 solution in terms of Li 6.15 Ga 0.25 La 2.8 Ce 0.1 Y 0.1 Zr2O 12 Use ammonia water as the precipitant to carry out co-precipitation with the feed solution. The pH during the precipitation reaction process is 9.3 - 10.6. After the precipitation precursor is filtered and washed, it is dried at 200 °C for 12 h. After drying, it is ball-milled and mixed with lithium carbonate. The ball-milling dispersion medium is isopropanol, the solid content is 25%, the ball-milling rotation speed is 500 rpm, and the ball-milling time is 12 h. The mixed slurry is dried and screened to obtain the second mixed precursor. The second mixed precursor is calcined in an air atmosphere at 600 °C for 4 h, at 740 °C for 5 h, then heated to 850 °C and calcined for 6 h, with a heating rate of 5 °C / min, and then cooled to room temperature with the furnace. After ball-milling at 500 rpm for 8 h to refine the particle size, it is dried and screened to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. The green compact is sintered at 1260 °C for 40 min to obtain the lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The ionic conductivity at room temperature is tested to be 9.01×10 -4 S / cm, the ceramic pores are about 0.030 per μm 2 , the average pore diameter inside the electrolyte is 0.69 μm, the density is 96.0%, the interfacial impedance to lithium after assembling the lithium symmetric battery is 104.1 Ω, and a constant current charge-discharge test is carried out on the ability of the electrolyte to resist the growth of lithium filaments at a current density of 0.2 mA cm 2 , and it can be stably cycled for 1788 h.

[0065] Example 7

[0066] Mix Li2CO3, La2O3, ZrO2, Ga2O3, CeO2, Sc2O3 and LiF according to Li 6.35 Ga 0.25 La 2.8 Ce 0.1 Sc 0.1 Zr2O11. 8F 0.2 Weigh according to stoichiometry and then put it into a ball milling jar for ball milling and mixing. The GaCe ratio is 2.5. The ball milling dispersion medium is isopropanol, the solid content is 25%, the ball milling speed is 500 rpm, and the ball milling time is 12 h. After drying and screening the mixed slurry, the first mixed precursor is obtained. After calcining the first mixed precursor in an air atmosphere at 740 °C for 5 h, it is heated to 900 °C and calcined for 6 h, with a heating rate of 5 °C / min. Subsequently, it is cooled to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, it is dried and screened to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. The green compact is sintered at 1260 °C for 40 min to obtain the lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The ionic conductivity at room temperature is tested to be 9.11×10 -4 S / cm, and the ceramic pores are about 0.026 pores / μm 2 , the average pore diameter inside the electrolyte is 0.91 μm, the relative density is 96.5%, the lithium interface impedance is 84.8 Ω after assembling the lithium symmetric battery, and the ability of the electrolyte to resist the growth of lithium filaments is tested by constant current charge and discharge at a current density of 0.2 mA cm 2 and it can be stably cycled for 1867 h.

[0067] Example 8

[0068] Weigh Li2CO3, La2O3, ZrO2, Ga2O3, CeO2, Fe2O3 and LiBr according to the stoichiometry of Li 6.5 Ga 0.25 Fe 0.05 La 2.9 Ce 0.1 Zr2O 11.5 Br 0.5 Weigh according to stoichiometry and then put it into a ball milling jar for ball milling and mixing. The GaCe ratio is 2.5. The ball milling dispersion medium is isopropanol, the solid content is 25%, the ball milling speed is 500 rpm, and the ball milling time is 12 h. After drying and screening the mixed slurry, the first mixed precursor is obtained. After calcining the first mixed precursor in an air atmosphere at 740 °C for 5 h, it is heated to 900 °C and calcined for 6 h, with a heating rate of 5 °C / min. Subsequently, it is cooled to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, it is dried and screened to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. The green compact is sintered at 1260 °C for 40 min to obtain the lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The ionic conductivity at room temperature is tested to be 8.61×10 -4 S / cm, and the ceramic pores are about 0.031 pores / μm 2, the average pore diameter inside the electrolyte is 0.69 μm, the relative density is 96.5%, the interfacial impedance to lithium after assembling the lithium symmetric battery is 84.8 Ω, and a constant current charge-discharge test is carried out at a current density of 0.2 mA / cm 2 to test the ability of the electrolyte to resist the growth of lithium filaments, and it can be stably cycled for 1867 h.

[0069] Example 9

[0070] Weigh LiNO3, La2O3, ZrO(NO3)2, Ga2O3, and CeO2 according to the stoichiometric ratio of Li 6.2 Ga 0.25 La 2.95 Ce 0.05 Zr2O 12 , put them into a ball milling tank for ball milling and mixing. The Ga:Ce ratio is 5. The ball milling dispersion medium is isopropyl alcohol, the solid content is 25%, the ball milling rotation speed is 500 rpm, and the ball milling time is 12 h. After drying and sieving the mixed slurry, the first mixed precursor is obtained. After calcining the first mixed precursor in an air atmosphere at 740 °C for 5 h, the temperature is raised to 900 °C and calcined for 6 h, with a heating rate of 5 °C / min. Then it is cooled to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, it is dried and sieved to obtain a lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. The green compact is sintered at 1250 °C for 60 min to obtain a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet. The lithium lanthanum zirconium composite oxide solid electrolyte has a garnet cubic phase structure. The ionic conductivity at room temperature is tested to be 9.14×10 -4 S / cm, and the ceramic pores are about 0.039 pores / μm 2 , the average pore diameter inside the electrolyte is 0.98 μm, the relative density is 96.0%, the interfacial impedance to lithium after assembling the lithium symmetric battery is 135.6 Ω, and a constant current charge-discharge test is carried out at a current density of 0.2 mA / cm 2 to test the ability of the electrolyte to resist the growth of lithium filaments, and it can be stably cycled for 1865 h.

[0071] Example 10

[0072] Mix the La(NO3)3 solution, ZrO(NO3)2 solution, Ga(NO3)3 solution, and Ce(NO3)3 solution according to the stoichiometric ratio of Li 6.1 Ga 0.25 La 2.95 Ce 0.15 Zr2O 12Prepare the stock solution with a stoichiometric ratio, where the Ga:Ce ratio is 1.67. Use ammonia water and ammonium bicarbonate as precipitants for co-precipitation with the stock solution. The pH during the precipitation reaction process is 9.8 - 11.1. After filtering and washing the precipitation precursor, dry it at 200 °C for 12 h. After drying, mix it with stoichiometric lithium carbonate by ball milling. The ball milling dispersion medium is isopropanol, the solid content is 25%, the ball milling speed is 500 rpm, and the ball milling time is 12 h. Dry the mixed slurry and then sieve it to obtain the second mixed precursor. Calcinate the second mixed precursor in an air atmosphere at 600 °C for 4 h, at 740 °C for 5 h, then raise the temperature to 850 °C and calcinate for 6 h with a heating rate of 5 °C / min, and then cool it to room temperature with the furnace. After ball milling at 500 rpm for 8 h to refine the particle size, dry and sieve it to obtain the lithium lanthanum zirconium composite oxide solid electrolyte powder. The lithium lanthanum zirconium composite oxide solid electrolyte powder is formed by isostatic pressing at 200 MPa and holding the pressure for 5 min to obtain a green compact. Sinter the green compact at 1250 °C for 60 min to obtain the lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet, which has a garnet cubic phase structure. The ionic conductivity at room temperature is tested to be 9.88×10 -4 S / cm, and the ceramic pores are about 0.025 pores / μm 2 , the average pore diameter inside the electrolyte is 0.54 μm, the relative density is 97.2%, the lithium interface impedance after assembling the lithium symmetric battery is 74.8 Ω, and use 0.2 mAcm 2 The constant current charge-discharge test of the current density is used to test the ability of the electrolyte to resist the growth of lithium filaments, and it can be stably cycled for 2011 h.

[0073] Examples 11 - 33

[0074] Except for the doping amounts of Ga and Ce, the corresponding chemical formula, lithium source, types of precipitants, powder calcination mechanism, and ceramic sintering mechanism, the other conditions are the same as those in Example 10. The specific parameters and performances of Examples 11 - 33 are shown in Tables 1 - 4 (pfu is performulaunit, per formula unit), and Examples 11 - 33 are without M compounds.

[0075] Examples 34 - 58

[0076] Except for the doping amounts of Ga and Ce, lithium source, powder calcination mechanism, and ceramic sintering mechanism, the other conditions are the same as those in Example 9. Examples 34 - 58 are shown in Tables 5 - 8, and Examples 34 - 58 are without M compounds.

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[0078]

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[0082]

[0083]

[0084]

[0085] It should be understood that the above specific embodiments of the present invention are only for illustrative explanation or interpretation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all variations and modifications that fall within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A lithium lanthanum zirconium composite oxide solid electrolyte, characterized in that The chemical general formula of the lithium lanthanum zirconium composite oxide solid electrolyte is Li 7-a Ga b La 3-c Ce c Zr 2-d M e O 12-f Z f , where M is a cation doping element, Z is an anion doping element, 0 < a ≤ 2, 0 < b ≤ 0.5, 0 < c ≤ 1.5, 0 ≤ d ≤ 1.5, 0 ≤ e ≤ 1.5, 0 ≤ f ≤ 0.5, 0 ≤ f ≤ 0.

5.

2. The lithium lanthanum zirconium composite oxide solid electrolyte according to claim 1, wherein In the lithium lanthanum zirconium composite oxide solid electrolyte, the content ratio of gallium to cerium is: 0.3 ≤ b / c ≤ 20.

3. The lithium lanthanum zirconium composite oxide solid electrolyte according to claim 1 or 2, characterized in that, The M includes at least one of cations Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W, P, In and rare earth elements, and the rare earth elements do not include La and Ce.

4. The lithium lanthanum zirconium composite oxide solid electrolyte according to claim 3, wherein, The Z includes at least one of anions S, F, Cl, Br and I.

5. The lithium lanthanum zirconium composite oxide solid electrolyte according to claim 1, 2 or 4, characterized in that, The density of the lithium lanthanum zirconium composite oxide all-solid electrolyte is ≥ 96%.

6. The lithium lanthanum zirconium composite oxide solid electrolyte according to claim 5, wherein The number of pores in the lithium lanthanum zirconium composite oxide solid electrolyte ≤ 0.05 pores / μm 2 , and the average pore diameter inside the electrolyte ≤ 1.2 μm.

7. The lithium lanthanum zirconium composite oxide solid electrolyte according to claim 1, 2, 4 or 6, characterized in that, The molar content of M does not exceed 8% of the total molar content of the solid electrolyte components, and the molar content of Z does not exceed 3% of the total molar content of the solid electrolyte components.

8. A method for preparing a lithium lanthanum zirconium composite oxide solid electrolyte according to any one of claims 1 to 7, characterized in that, It includes the following steps: S1. Compounding lithium compound, gallium compound, lanthanum compound, cerium compound, zirconium compound, M compound and Z compound according to a preset stoichiometric ratio to obtain a mixed precursor; the compounding treatment includes physical treatment or chemical treatment; S2. Calcining, ball milling, drying and classifying the mixed precursor to obtain a lithium lanthanum zirconium composite oxide solid electrolyte powder; the lithium lanthanum zirconium composite oxide solid electrolyte powder is a kind of lithium lanthanum zirconium composite oxide solid electrolyte.

9. The preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte according to claim 8, characterized in that, The method further includes S3: Processing the lithium lanthanum zirconium composite oxide solid electrolyte powder obtained in S2 to obtain any one of a lithium lanthanum zirconium composite oxide solid electrolyte ceramic sheet, film and tape.

10. The method according to claim 8, wherein The mixed precursor includes a first mixed precursor and a second mixed precursor. The first mixed precursor is prepared by physical treatment, and the second mixed precursor is prepared by chemical treatment.

11. The method according to claim 10, wherein The physical treatment in S1 includes: Adding lithium compound, gallium compound, lanthanum compound, cerium compound, zirconium compound, M compound and Z compound according to a preset stoichiometric ratio into a dispersion medium for ball milling and mixing, and drying to obtain a first mixed precursor.

12. The method according to claim 10, wherein The chemical treatment in S1 includes: Carrying out a precipitation reaction on the solutions of gallium compound, lanthanum compound, cerium compound, zirconium compound and the co-precipitable M compound corresponding thereto according to a preset stoichiometric ratio, filtering and washing to obtain a precipitate, and then mixing the precipitate with lithium compound, the remaining non-co-precipitable M compound and Z compound evenly according to a preset stoichiometric ratio to obtain a second mixed precursor. In the chemical treatment, the M compound includes a co-precipitable M compound and a non-co-precipitable M compound.

13. The preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte according to claim 11, wherein In the physical treatment, the ball milling speed is controlled at 200 - 800 rpm, the ball milling time is 1 - 24 h, the drying temperature is 50 - 200 °C, and the drying time is 4 - 24 h.

14. The preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte according to claim 12, characterized in that, In the chemical treatment, the pH value of the precipitation reaction is controlled at 9 - 12, and the precipitation reaction temperature is 5 - 40 °C.

15. The preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte according to claim 8, characterized in that, In the S2 step, the calcining temperature is controlled at 600 - 1100 °C, and the calcining time is 30 min - 24 h.

16. The preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte according to claim 8, characterized in that, The calcining atmosphere in the S2 step includes at least one of air, oxygen, nitrogen, helium and argon.

17. The preparation method of the lithium lanthanum zirconium composite oxide solid electrolyte according to claim 9, characterized in that, In the step S3, the processing temperature is 900 to 1350 °C, and the processing time is 30 min to 24 h.

18. Application of the lithium lanthanum zirconium composite oxide solid electrolyte according to any one of claims 1 to 7 or the lithium lanthanum zirconium composite oxide solid electrolyte obtained by the preparation method according to any one of claims 8 to 17 in all-solid-state lithium metal or lithium-ion batteries, semi-solid-state lithium-ion batteries, and lithium-air batteries.

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