Perovskite type solid electrolyte, preparation method thereof and lithium ion battery

Abstract

The invention relates to a perovskite type solid electrolyte, a preparation method thereof and a lithium ion battery. The chemical formula of the perovskite type solid electrolyte is LaiAaLabBb (TiCC1C2C2C3C3C4C4C5C5C6C6) OdXd, 0.08 < = a < = a < = a + a < = 1, and a > = 0; 0 < = b < = b < = b + b < = 2; 0 < = c + c1 + c2 + c3 + c4 + c5 + c6 < = 3, and at least four of c1, c2, c3, c4, c5 and c6 are not equal to 0; 0 < = d < = d < = d + d < = 9, d > = 0; wherein A is selected from Li-site doping elements; b is selected from one or more of Sr, Na, Nd, Pr, Sm, Gd, Dy, Y, Eu, Tb, Ba and Bi; c1, C2, C3, C4, C5 and C6 are independently selected from one or more of Mg, W, Mn, Ge, Ru, Nb, Ta, Co, Zr, Hf, Fe, Cr and Ga, and at least four of C1, C2, C3, C4, C5 and C6 are different; x is a monovalent, divalent or trivalent anion. According to the perovskite type solid electrolyte, through high-entropy doping design, at least four different doping elements are introduced into a Ti site, a multi-principal-element high-entropy perovskite structure is formed, and the performance, especially the ionic conductivity, of an LLTO material is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a perovskite solid electrolyte and its preparation method, and a lithium-ion battery. Background Technology

[0002] Currently, lithium-ion batteries have attracted widespread attention from various energy storage systems due to their high voltage, high specific capacity, and green, pollution-free characteristics. The development of new energy vehicles has also placed higher demands on lithium-ion batteries. Lithium-ion batteries with higher energy density, longer lifespan, and higher safety have become key to technological innovation in new energy vehicles. Traditional lithium-ion batteries use organic electrolytes, whose flammable and leak-prone characteristics can lead to safety accidents. Solid-state lithium metal batteries, which use non-flammable solid electrolytes instead of organic electrolytes and are directly matched with lithium metal anodes, have broad prospects.

[0003] The core of solid-state batteries is the solid-state electrolyte, which is mainly classified into organic, inorganic, and composite solid-state electrolytes. Inorganic solid-state electrolytes primarily include oxides, sulfides, halides, and various novel lithium-ion conductors. High-entropy materials are high-mixed-entropy structures composed of multiple main elements. In the field of oxide solid-state electrolytes, high-entropy garnet and Nasicon-type oxide solid-state electrolytes have been reported. Perovskite-type oxide solid-state electrolytes (LLTO) are a typical type of oxide solid-state electrolyte, first reported by Yoshiyuku Inaguma in 1993. They possess a typical ABO3 structure, exhibiting high intracrystalline ionic conductivity but low grain boundary ionic conductivity.

[0004] Currently, there are no reports on LLTO high-entropy materials. Summary of the Invention

[0005] Therefore, it is necessary to provide a high-entropy perovskite solid electrolyte and its preparation method, as well as a lithium-ion battery, to address the issue of how to improve ionic conductivity.

[0006] A perovskite-type solid electrolyte, wherein the chemical formula of the perovskite-type solid electrolyte is Li a A a` La b B b` (Ti C C1 C1 C2 C2 C3 C3 C4 C4 C5 C5 C6 C6 )O d X d`Among them, 0.08≦a`≦a≦a+a`≦1, a`≧0; 0≦b`≦b≦b+b`≦2; 0≦c+c1+c2+c3+c4+c5+c6≦3, and at least four of c1, c2, c3, c4, c5, and c6 are not equal to 0; 0≦d`≦d≦d+d`≦9, d`≧0; where: A is selected from Li-site doped elements; B is selected from one or more of Sr, Na, Nd, Pr, Sm, Gd, Dy, Y, Eu, Tb, Ba and Bi; C1, C2, C3, C4, C5 and C6 are each independently selected from one or more of Mg, W, Mn, Ge, Ru, Nb, Ta, Co, Zr, Hf, Fe, Cr and Ga, and at least four of C1, C2, C3, C4, C5 and C6 are different; X is one or more of the following: monovalent, divalent, or trivalent anions.

[0007] The perovskite solid electrolyte of this invention employs a high-entropy doping design, introducing at least four different doping elements at the Ti sites to form a multi-principal-element high-entropy perovskite structure. This high degree of lattice distortion effectively improves the performance of LLTO materials, especially their ionic conductivity.

[0008] In one embodiment, A is selected from one or more of H, Al, B and Be.

[0009] In one embodiment, B is selected from at least one of Nd, Pr, Gd, Sm, Dy, Y, Eu, Tb and Bi.

[0010] In one embodiment, c1, c2, c3, c4, c5, and c6 are all non-zero.

[0011] In one embodiment, X is selected from one or more of N, B, S, Cl, F, Br and I.

[0012] A method for preparing any of the above-mentioned perovskite-type solid electrolytes includes the following steps: Weigh the raw materials according to the stoichiometric ratio and prepare a mixture; The mixture is subjected to a first ball milling to obtain a ball mill slurry; The ball-milled slurry was dried and then calcined to obtain calcined powder; The calcined powder is then ball-milled a second time to obtain secondary ball-milled powder. The secondary ball-milled powder is pressed into ceramic sheets; and The ceramic sheet is sintered to obtain a perovskite-type solid electrolyte.

[0013] This preparation method employs a two-stage ball milling process combined with intermediate calcination. The first ball milling ensures uniform mixing of the raw materials at the atomic / molecular level, laying the foundation for the subsequent formation of a homogeneous high-entropy phase. The intermediate calcination step allows the material to initially form the target perovskite phase. The second ball milling effectively breaks up the hard agglomerates formed after calcination, significantly reducing the powder particle size and increasing sintering activity, thereby obtaining a high-density, clean-grain-bound, and low-resistivity electrolyte sheet in the final sintering step. This method is simple, easy to control, and suitable for large-scale production.

[0014] In one embodiment, the ball mill slurry is dried and then calcined at a temperature of 1000℃~1200℃ for 6 hours~12 hours.

[0015] In one embodiment, the ceramic sheet is sintered by pre-sintering it at 800°C to 900°C for 2 to 4 hours, and then holding it at 1200°C to 1400°C for 10 to 14 hours.

[0016] In one embodiment, the first ball milling time is 6 to 12 hours, and the second ball milling time is 6 to 12 hours.

[0017] A lithium-ion battery comprising any of the above-mentioned perovskite-type solid electrolytes.

[0018] Lithium-ion batteries assembled using the high-ionic-conductivity perovskite solid electrolyte prepared according to this invention exhibit enhanced safety and stability, fundamentally avoiding the risks of liquid electrolyte leakage and combustion. Simultaneously, the high ionic conductivity helps reduce battery internal resistance, improve rate performance and power density, enabling the battery to support fast charging and facilitating matching with high-capacity lithium metal anodes, thereby increasing the overall energy density of the battery system. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for preparing a perovskite-type solid electrolyte according to an embodiment of the present invention. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] One embodiment of the perovskite-type solid electrolyte has the chemical formula Li a A a` La b B b` (Ti C C1 C1 C2 C2 C3 C3 C4 C4 C5 C5 C6 C6 )O d X d` Among them, 0.08≦a`≦a≦a+a`≦1, a`≧0; 0≦b`≦b≦b+b`≦2; 0≦c+c1+c2+c3+c4+c5+c6≦3, and at least four of c1, c2, c3, c4, c5, and c6 are not equal to 0; 0≦d`≦d≦d+d`≦9, d`≧0; where: A is selected from Li-site doped elements; B is selected from one or more of Sr, Na, Nd, Pr, Sm, Gd, Dy, Y, Eu, Tb, Ba and Bi; C1, C2, C3, C4, C5 and C6 are each independently selected from one or more of Mg, W, Mn, Ge, Ru, Nb, Ta, Co, Zr, Hf, Fe, Cr and Ga, and at least four of C1, C2, C3, C4, C5 and C6 are different; X is one or more of the following: monovalent, divalent, or trivalent anions.

[0023] The perovskite solid electrolyte of this embodiment employs a high-entropy doping design, introducing at least four different doping elements at the Ti sites to form a multi-principal-element high-entropy perovskite structure. This high degree of lattice distortion effectively improves the performance of LLTO materials, especially their ionic conductivity.

[0024] Based on the aforementioned embodiments, A is selected from one or more of H, Al, B and Be; these doped structures help stabilize the lithium layer structure and may form some oxygen vacancies, further promoting the migration of lithium ions, while having little impact on electronic conductivity, which is beneficial for maintaining good insulation of the electrolyte.

[0025] Based on the aforementioned embodiments, B is selected from at least one of Nd, Pr, Gd, Sm, Dy, Y, Eu, Tb, and Bi. Introducing rare earth or rare earth-like elements into the La site can improve the performance of LLTO materials. More preferably, B is selected from four or more of Nd, Pr, Gd, Sm, Dy, Y, Eu, Tb, and Bi. Multiple doping at the La site can further enhance the high-entropy effect.

[0026] It is understood that this application is limited to multi-element doping at the La site, but does not exclude multi-element doping at the Li site and the La site. Based on the formation of multi-doping at the La site, the technical solution of single doping or multi-doping at the La site and / or Li site should still be considered within the scope of protection of this application.

[0027] Based on the aforementioned implementation method, c1, c2, c3, c4, c5, and c6 are all non-zero. When c1 to c6 are all non-zero, it means that all six elements are fully co-doped at the La sites of the perovskite structure. This extreme high-entropy configuration produces the strongest lattice distortion and synergistic stabilization effect, which not only significantly widens the lithium-ion migration channels and lowers the migration energy barrier, but also effectively purifies and optimizes the grain boundary structure and composition. This synergistically achieves a significant reduction in grain boundary resistance and a breakthrough increase in total ionic conductivity, while ensuring the material's excellent structural stability and microstructure compactness.

[0028] Based on the aforementioned embodiments, X is selected from one or more of N, B, S, Cl, F, Br, and I. By partially doping the anion sites (O sites), especially by introducing more electronegative halide ions such as F and Cl, the lattice energy can be adjusted, the strength of the metal-oxygen (or oxygen-like) bond can be enhanced, the structural stability of the material and its chemical stability to the lithium metal anode can be improved, and additional lattice defects may be introduced to assist lithium-ion conduction.

[0029] The perovskite solid electrolyte of this invention employs a high-entropy doping design, introducing at least four different doping elements at the Ti sites to form a multi-principal-element high-entropy perovskite structure. This high degree of lattice distortion effectively improves the performance of LLTO materials, especially their ionic conductivity.

[0030] Please see Figure 1 The preparation method of the perovskite-type solid electrolyte according to one embodiment of the present invention includes the following steps: S10. Weigh the raw materials according to the stoichiometric ratio and prepare them into a mixture.

[0031] Based on the target chemical formula Li a A a` La b B b` (Ti C C1C1 C2 C2 C3 C3 C4 C4 C5 C5 C6 C6 )O d X d` Within the range, determine the precise molar ratio of each element. Taking into account the chemical formula of the raw materials (e.g., La2O3 contains 2 La atoms) and possible volatility (e.g., lithium volatilizes at high temperatures, usually requiring an additional 5%~10% lithium source as compensation), perform precise molar mass conversion and mass calculation.

[0032] The lithium source can be, for example, lithium hydroxide (LiOH·H2O), lithium carbonate (Li2CO3), or lithium nitrate (LiNO3). LiOH·H2O is preferred because it has a lower decomposition temperature and higher reactivity.

[0033] Among them, the lanthanum source is, for example, lanthanum oxide (La2O3).

[0034] For element A sources (H, Fe, Ga, Al, B, Be), depending on the choice of A, its oxides (such as Al2O3, Ga2O3, B2O3), carbonates, or corresponding lithium salts and nitrates can be used.

[0035] For element B sources (Sr, Na, Nd, Pr, Sm, Gd, Dy, Y, Eu, Tb, Ba, Bi), their oxides (such as Nd₂O₃, Pr₆O₃) are typically used. 11 Gd2O3, Bi2O3), carbonates (such as SrCO3, BaCO3) or nitrates.

[0036] For titanium and carbon source (Mg, W, Mn, Ge, Ru, Nb, Ta, Co, Zr, Hf, Fe, Cr, Ga), their oxides (such as TiO2, ZrO2, Nb2O5, Ta2O5) are usually used.

[0037] For the X element source (N, B, S, Cl, F, Br, I), for anion doping, the corresponding lithium salt (such as LiF, LiCl, LiBr, LiI) or ammonium salt (such as NH4F) can be used, or it can be introduced by sintering under a specific atmosphere (such as N2 or H2S).

[0038] S20. The mixture obtained in step S10 is subjected to ball milling for the first time to obtain ball mill slurry.

[0039] In one embodiment, the first ball milling time is 6 to 12 hours.

[0040] S30. The ball mill slurry obtained in step S20 is dried and then calcined to obtain calcined powder.

[0041] In one embodiment, the calcination temperature after drying the ball-milled slurry is 1000℃~1200℃, and the calcination time is 6 hours~12 hours. This temperature and time range ensures that the precursor reacts fully and forms the desired perovskite crystal structure completely, while avoiding abnormal grain growth or element volatilization due to excessively high temperature or time, thus ensuring the formation and compositional uniformity of the high-entropy phase.

[0042] Furthermore, the calcination temperature after drying the ball mill slurry can be, but is not limited to, 1000℃, 1050℃, 1100℃, 1150℃ or 1200℃, and the calcination time can be, but is not limited to, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.

[0043] S40. The calcined powder obtained in step S30 is subjected to a second ball milling to obtain a second ball-milled powder.

[0044] In one embodiment, the second ball milling time is 6 to 12 hours.

[0045] S50. Press the secondary ball-milled powder obtained in step S40 into ceramic sheets.

[0046] S60. Sinter the ceramic sheet obtained in step S50 to obtain a perovskite solid electrolyte.

[0047] In one embodiment, the sintering process for the ceramic sheet involves pre-sintering the ceramic sheet at 800℃~900℃ for 2~4 hours, followed by holding at 1200℃~1400℃ for 10~14 hours. This two-step sintering method allows for the initial removal of organic matter and binders from the green body through low-temperature pre-sintering, giving the green body a certain initial strength and preventing cracking or deformation caused by direct high-temperature sintering. The subsequent high-temperature, long-term holding sintering promotes full grain growth and grain boundary migration, achieving high densification of the ceramic body and obtaining electrolyte sheets with low porosity and high mechanical strength. This is crucial for improving ionic conductivity and battery safety.

[0048] Furthermore, the pre-sintering temperature of the ceramic sheets can be, but is not limited to, 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, or 900℃, and the pre-sintering time can be, but is not limited to, 2 hours, 3 hours, or 4 hours; the holding sintering temperature can be, but is not limited to, 1200℃, 1250℃, 1300℃, 1350℃, or 1400℃, and the holding sintering time can be, but is not limited to, 10 hours, 11 hours, 12 hours, 13 hours, or 14 hours.

[0049] This preparation method employs a two-stage ball milling process combined with intermediate calcination. The first ball milling ensures uniform mixing of the raw materials at the atomic / molecular level, laying the foundation for the subsequent formation of a homogeneous high-entropy phase. The intermediate calcination step allows the material to initially form the target perovskite phase. The second ball milling effectively breaks up the hard agglomerates formed after calcination, significantly reducing the powder particle size and increasing sintering activity, thereby obtaining a high-density, clean-grain-bound, and low-resistivity electrolyte sheet in the final sintering step. This method is simple, easy to control, and suitable for large-scale production.

[0050] One embodiment of the lithium-ion battery includes any of the perovskite-type solid electrolytes described above.

[0051] Lithium-ion batteries assembled using the high-ionic-conductivity perovskite solid electrolyte prepared according to this invention exhibit enhanced safety and stability, fundamentally avoiding the risks of liquid electrolyte leakage and combustion. Simultaneously, the high ionic conductivity helps reduce battery internal resistance, improve rate performance and power density, enabling the battery to support fast charging and facilitating matching with high-capacity lithium metal anodes, thereby increasing the overall energy density of the battery system.

[0052] Referring to the above embodiments, in order to make the technical solution of the present invention more specific, clear and easy to understand, examples of the technical solution of the present invention are given below. However, it should be noted that the content to be protected by the present invention is not limited to the following embodiments.

[0053] Example 1 Weigh lithium hydroxide, lanthanum oxide, tungsten oxide, manganese oxide, germanium oxide, and titanium dioxide according to stoichiometric ratios and prepare a mixture. Using anhydrous ethanol as a medium, the mixture was added to a ball mill jar for the first ball milling, which lasted for 6 hours, to obtain a ball mill slurry. After drying the ball mill slurry, it was placed in a crucible and calcined at 1100℃ for 6 hours to obtain calcined powder. The calcined powder was ball-milled a second time for 6 hours to obtain the second ball-milled powder. The powder from the secondary ball milling process is dried and placed in a mortar, then ground thoroughly to obtain a second particle. The second particle is then pressed into a ceramic sheet. The ceramic sheet was sintered at 850°C for 2 hours, and then sintered at 1300°C for 12 hours to obtain the electrolyte sheet of Example 1, which has the molecular formula LiLa0.4Nd0.4Pr0.4Gd0.4Bi0.4Ti3O9.

[0054] Example 2 Lithium hydroxide, lanthanum oxide, tungsten oxide, manganese oxide, tantalum oxide, zirconium oxide, and titanium dioxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₆W₀.₆Mn₀.₆Ta₀.₆Zr₀.₆O₉.

[0055] Example 3 Lithium hydroxide, lanthanum oxide, manganese oxide, germanium oxide, tantalum oxide, chromium oxide, and titanium dioxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₆Mn₀.₆Ge₀.₆Ta₀.₆Cr₀.₆O₉.

[0056] Example 4 Lithium hydroxide, lanthanum oxide, niobium oxide, tantalum oxide, zirconium oxide, hafnium oxide, and titanium dioxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₆Nb₀.₆Ta₀.₆Zr₀.₆Hf₀.₆O₉.

[0057] Example 5 Lithium hydroxide, lanthanum oxide, tungsten oxide, manganese oxide, germanium oxide, zirconium oxide, and titanium dioxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₁.₀W₀.₃Mn₀.₅Ge₀.₆Zr₀.₆O₉.

[0058] Example 6 Lithium hydroxide, lanthanum oxide, manganese oxide, niobium oxide, tantalum oxide, iron oxide, and titanium dioxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa2Ti1.2Mn0.5Nb0.5Ta0.4Fe0.4O9.

[0059] Example 7 Lithium hydroxide, lanthanum oxide, titanium oxide, magnesium oxide, tungsten oxide, manganese oxide, gallium oxide, and LiCl were weighed according to stoichiometric ratios as precursors. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₉Mg₀.₆W₀.₅Mn₀.₅Ga₀.₅O₈.₁Cl₀.₉.

[0060] Example 8 Lithium hydroxide, lanthanum oxide, titanium oxide, germanium oxide, tantalum oxide, cobalt oxide, zirconium oxide, and LiI were weighed according to stoichiometric ratios as precursors. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₆Ge₀.₆Ta₀.₆Co₀.₆Zr₀.₆O₈.₃I₀.₇.

[0061] Example 9 Lithium hydroxide, lanthanum oxide, titanium oxide, tantalum oxide, iron oxide, chromium oxide, and gallium oxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₅Ta₀.₇Fe₀.₆Cr₀.₆Ga₀.₆O₉.

[0062] Example 10 Lithium hydroxide, lanthanum oxide, titanium oxide, zirconium oxide, hafnium oxide, iron oxide, and gallium oxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₉Zr₀.₈Hf₀.₄Fe₀.₄Ga₀.₅O₉.

[0063] Example 11 Lithium hydroxide, lanthanum oxide, titanium oxide, magnesium oxide, tungsten oxide, manganese oxide, and iron oxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₆Mg₀.₆W₀.₆Mn₀.₆Fe₀.₆O₉.

[0064] Example 12 Lithium hydroxide, lanthanum oxide, titanium oxide, hafnium oxide, iron oxide, chromium oxide, and gallium oxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₀.₆Hf₀.₆Fe₀.₆Cr₀.₆Ga₀.₆O₉.

[0065] Example 13 Lithium hydroxide, lanthanum oxide, neodymium oxide, titanium oxide, tungsten oxide, manganese oxide, tantalum oxide, cobalt oxide, and LiCl were weighed according to stoichiometric ratios as precursors. The preparation method was the same as in Example 1. Its molecular formula is LiLa1.8Nd0.2Ti0.6W0.6Mn0.6Ta0.6Co0.6O8.1Cl0.9.

[0066] Comparative Example 1 Lithium hydroxide, lanthanum oxide, and titanium dioxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂Ti₃O₉.

[0067] Comparative Example 2 Lithium hydroxide, lanthanum oxide, titanium oxide, zirconium oxide, hafnium oxide, and gallium oxide were weighed according to stoichiometric ratios and prepared into a mixture. The preparation method was the same as in Example 1. Its molecular formula is LiLa₂TiO₃. 75 Zr0. 75 Hf0. 75 Ga0. 75 O9.

[0068] Performance testing: The ionic conductivity of the electrolyte sheets in Examples 1 to 8 and Comparative Examples 1 to 2 was tested using the following methods, and the test results are shown in Table 1.

[0069] Test method: Under an argon atmosphere (water ≤ 0.01 ppm, oxygen ≤ 0.01 ppm), weigh 100 mg ± 1 mg of sample powder and pour it into the assembled semi-mold. Then, flatten and assemble the full mold. After adding insulating covers to the top and bottom of the full mold, place it inside the outer metal frame and tighten the screws. Apply pressure of 3T to the entire mold, tighten the screws again, maintain the pressure for 1 minute, and then release the pressure. Connect to an electrochemical workstation for EIS testing. Test range: 100 mHz~7 mHz. After the EIS (electrochemical impedance spectroscopy) test is completed, fit the test curve using Z-view software to obtain the impedance value R. Remove the mold from the glove box and test the thickness L of the compressed powder tablet. Calculate the ionic conductivity σ = L / (R*S), in mS / cm, where S is calculated from the mold diameter φ10.

[0070] Table 1 As can be seen from Table 1, the various embodiments of the present invention, through high-entropy doping of the Ti site (at least four different C elements), achieve ionic conductivity (10... -4 The S / cm ratio was significantly higher than that of the undoped comparative example 1 (on the order of magnitude). -6 (on the order of S / cm) and Comparative Example 2 (10) which only underwent conventional doping. -5 The conductivity (on the order of S / cm) is increased by one to two orders of magnitude. This fully demonstrates the effectiveness and superiority of the high-entropy design strategy of this invention in improving the ionic conductivity of perovskite solid electrolytes, especially in solving the bottleneck problem of low grain boundary conductivity.

[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A perovskite-type solid electrolyte, characterized in that, The chemical formula of the perovskite-type solid electrolyte is Li a A a` La b B b` (Ti C C1 C1 C2 C2 C3 C3 C4 C4 C5 C5 C6 C6 )O d X d` Among them, 0.08≦a`≦a≦a+a`≦1, a`≧0; 0≦b`≦b≦b+b`≦2; 0≦c+c1+c2+c3+c4+c5+c6≦3, and at least four of c1, c2, c3, c4, c5, and c6 are not equal to 0; 0≦d`≦d≦d+d`≦9, d`≧0; where: A is selected from Li-site doped elements; B is selected from one or more of Sr, Na, Nd, Pr, Sm, Gd, Dy, Y, Eu, Tb, Ba and Bi; C1, C2, C3, C4, C5 and C6 are each independently selected from one or more of Mg, W, Mn, Ge, Ru, Nb, Ta, Co, Zr, Hf, Fe, Cr and Ga, and at least four of C1, C2, C3, C4, C5 and C6 are different; X is one or more of the following: monovalent, divalent, or trivalent anions.

2. The perovskite-type solid electrolyte according to claim 1, characterized in that, The A is selected from one or more of H, Al, B and Be.

3. The perovskite-type solid electrolyte according to claim 1, characterized in that, The B is selected from at least one of Nd, Pr, Gd, Sm, Dy, Y, Eu, Tb and Bi.

4. The perovskite-type solid electrolyte according to claim 1, characterized in that, c1, c2, c3, c4, c5, and c6 are all non-zero.

5. The perovskite-type solid electrolyte according to claim 1, characterized in that, X is selected from one or more of N, B, S, Cl, F, Br and I.

6. A method for preparing a perovskite-type solid electrolyte according to any one of claims 1 to 5, characterized in that, Includes the following steps: Weigh the raw materials according to the stoichiometric ratio and prepare a mixture; The mixture is subjected to a first ball milling to obtain a ball mill slurry; The ball-milled slurry was dried and then calcined to obtain calcined powder; The calcined powder is then ball-milled a second time to obtain secondary ball-milled powder. The secondary ball-milled powder is pressed into ceramic sheets; and The ceramic sheet is sintered to obtain a perovskite-type solid electrolyte.

7. The method for preparing the perovskite-type solid electrolyte according to claim 6, characterized in that, The ball mill slurry is dried and then calcined at a temperature of 1000℃~1200℃ for 6 hours~12 hours.

8. The method for preparing the perovskite-type solid electrolyte according to claim 6, characterized in that, The ceramic sheet is sintered as follows: the ceramic sheet is pre-sintered at 800℃~900℃ for 2 to 4 hours, and then sintered at 1200℃~1400℃ for 10 to 14 hours.

9. The method for preparing the perovskite-type solid electrolyte according to claim 6, characterized in that, The first ball milling time is 6 to 12 hours, and the second ball milling time is 6 to 12 hours.

10. A lithium-ion battery, characterized in that, The perovskite-type solid electrolyte includes any one of claims 1 to 5.

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