Modified oxide solid electrolyte material and preparation method and application thereof

Abstract

The invention provides a modified oxide solid electrolyte material as well as a preparation method and application thereof. According to the technical scheme, the method comprises the three steps of synthesis of modified lithium borate, synthesis of zirconium lithium borate and secondary high-temperature modification, and raw material selection types, mixing proportions, reaction conditions and the like are optimized in each step. Aiming at the defects of the traditional high-temperature solid-phase synthesis method, by innovating raw material combination and process steps, the reaction temperature is reduced, the product purity and the production efficiency are improved, and energy conservation and emission reduction are realized. Through Cu / Ti / Al / P / N bulk phase doping and Ta / Al / La / Li surface doping and coating, the ionic conductivity, the rate capability and the like are improved, and the application range is widened.

Description

Technical Field

[0001] The present invention relates to the technical fields of inorganic material preparation and lithium battery raw materials, and particularly relates to a modified oxide solid electrolyte material, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of new energy vehicles, the research and industrialization processes of semi-solid and all-solid batteries with high safety and high energy density have been accelerating continuously. However, the key factor affecting or restricting them is the solid electrolyte. The current technical routes of solid electrolytes are oxide solid electrolytes, polymer solid electrolytes, sulfide solid electrolytes, and halide solid electrolytes. Each of these solid electrolytes has both advantages and disadvantages. Among them, oxide solid electrolytes have advantages such as high safety, long cycle life, good thermal stability, relatively mature processes, and rich raw materials. However, there are also objective problems such as relatively low ionic conductivity (compared with sulfides and polymers), large interfacial contact resistance, and high process difficulty. How to improve ionic conductivity and stability, reduce contact resistance, process difficulty, and cost is a problem that needs to be solved in current research and industrialization technologies. With the continuous progress of materials science, lithium zirconium borate, as an inorganic material with multiple functional characteristics, has significant application value in fields such as ceramics, glass, and catalysts. However, traditional preparation technologies such as high-temperature solid-phase synthesis method have inherent defects such as high energy consumption, difficult-to-control purity, and low production efficiency. Therefore, an innovative preparation scheme is urgently needed. Summary of the Invention

[0003] One of the purposes of the present invention is to provide a preparation method of a modified oxide solid electrolyte. This modification strategy can improve the voltage stability and electrode compatibility of the electrolyte, thereby enhancing the overall performance and safety performance of the battery. This method can not only improve the performance of the solid electrolyte, increase ionic conductivity, but also enhance the product purity and production efficiency while reducing the reaction temperature, thereby achieving energy conservation and emission reduction and promoting green production.

[0004] Another purpose of the present invention is to provide a modified oxide solid electrolyte prepared by the above preparation method.

[0005] A third purpose of the present invention is to provide an application of the modified oxide solid electrolyte.

[0006] In order to achieve the above purposes of the present invention, the following technical solutions are specifically adopted:

[0007] In the first aspect, the present invention provides a preparation method of a modified oxide solid electrolyte material, including the following steps:

[0008] (1) Mix BLiO2, Li2O, B4Li2O7, and LiF by ball milling to obtain the initial lithium borate, and then perform pre-sintering to obtain fluorine-doped modified lithium borate;

[0009] (2) Dry mix and ball mill the fluorine-doped modified lithium borate from step (1) with a zirconium source, a lithium source, and a dopant to obtain a mixture containing lithium zirconium borate (LZBO);

[0010] (3) Press the mixture containing lithium zirconium borate (LZBO) from step (2) into tablets and transfer them to a primary sintering device. Perform high-temperature primary sintering in dry air or an inert atmosphere under slightly positive or slightly negative pressure, and then obtain doped and modified lithium zirconium borate after air flow crushing, sieving, and demagnetization;

[0011] (4) Dry mix and ball mill the doped and modified lithium zirconium borate from step (3) with a coating agent, press it into tablets and transfer it to a secondary sintering device. Perform high-temperature secondary sintering in dry air or an inert atmosphere under slightly positive or slightly negative pressure, and then obtain the finished product of coated and modified lithium zirconium borate (i.e., the modified oxide solid electrolyte material) after air flow crushing, sieving, and demagnetization.

[0012] The following is a detailed description:

[0013] Step (1):

[0014] Mix BLiO2, Li2O, B4Li2O7, and LiF by ball milling under certain conditions in a certain proportion to obtain the initial lithium borate, and then perform low-temperature pre-sintering under certain conditions to obtain fluorine-doped modified lithium borate.

[0015] In some embodiments, the mass ratio of BLiO2, Li2O, B4Li2O7, and LiF in step (1) is 0.6 - 1:0.6 - 1:0.5 - 1:0.0001 - 0.02, preferably 0.8 - 1:0.8 - 1:0.6 - 1:0.0006 - 0.018, and more preferably 1:1:1:0.001 - 0.015;

[0016] In some embodiments, the ball milling speed in step (1) is 100 - 1500 rpm, preferably 200 - 1400 rpm, and more preferably 300 - 1280 rpm;

[0017] In some embodiments, the ball milling time in step (1) is 0.5 - 8.0 h, preferably 1.0 - 6.0 h, and more preferably 2.0 - 5.0 h;

[0018] In some embodiments, the ball-to-material ratio in step (1) is 2 - 20:1, preferably 3 - 18:1, and more preferably 3 - 12:1;

[0019] In some embodiments, the constant temperature of pre-sintering in step (1) is 100 - 800 °C, preferably 200 - 740 °C, more preferably 300 - 680 °C;

[0020] In some embodiments, the constant temperature time of pre-sintering in step (1) is 1.0 - 6.0 h, preferably 1.5 - 5.0 h, more preferably 2.0 - 4.0 h;

[0021] In some embodiments, the purities of BLiO2, Li2O, and B4Li2O7 in step (1) are all ≥ 99.9%, and their D50 particle sizes are 1.0 μm - 15.0 μm, preferably 2.0 μm - 12.0 μm, more preferably 2.0 μm - 8.0 μm;

[0022] In some embodiments, the purity of LiF in step (1) is ≥ 99.95%, and its D50 particle size is 0.5 μm - 5.0 μm, preferably 0.5 μm - 4.0 μm, more preferably 0.5 μm - 2.5 μm;

[0023] In some embodiments, the pre-sintering atmosphere in step (1) is one of argon and nitrogen;

[0024] In some embodiments, the mixing and ball-milling equipment in step (1) is a high-energy ball mill, a ball mill, a pot mill, etc.;

[0025] In some embodiments, the medium used for mixing and ball-milling in step (1) is one of zirconia balls, agate balls, stainless steel grinding balls, and cemented carbide grinding balls, preferably zirconia balls or agate balls;

[0026] In some embodiments, the equipment for pre-sintering in step (1) is one of a microwave synthesizer, a microwave reactor, a microwave catalytic synthesizer, a vacuum box-type atmosphere furnace, a vacuum tube furnace, and a rotary furnace; preferably a microwave catalytic synthesizer and a vacuum box-type atmosphere furnace.

[0027] In some embodiments, the initial particle size of lithium borate after mixing and ball-milling in step (1) is 0.8 - 1.2 μm.

[0028] Step (2):

[0029] The lithium borate doped with fluorine in step (1) is dry-mixed / ball-milled with a zirconium source, a lithium source, and a dopant in a certain proportion to obtain a mixture containing lithium zirconium borate;

[0030] In some embodiments, the zirconium source in step (2) is selected from Zr(CO3)2, Zr(OH)4, ZrO2, Zr 0.92 O2Y 0.08 、Zr 0.97 O2Y 0.03, one or more of Zr(CH3COO)4, ZrB2, ZrF4, ZrSiO4, Li2ZrO3, Zr(HPO4)2, ZrCl4, Zr(CH3COO)4·4H2O, Zr(C6H5O7)2, Zr(NO3)4, ZrS2;

[0031] Preferably, the zirconium source is one or more of Zr(CO3)2, Zr(OH)4, ZrO2, Zr 0.92 O2Y 0.08 , Zr 0.97 O2Y 0.03 ;

[0032] In some embodiments, the lithium source in step (2) is one or more selected from LiOH, LiOH·H2O, Li2CO3, LiNO3, Li3BO3, LiBO2, Li2O, LiI, LiCl or C2H3O2Li;

[0033] Preferably, the lithium source is one or more of Li2O, Li2CO3, LiOH·H2O;

[0034] In some embodiments, the dopant in step (2) is one or two or more combinations selected from Cu3N, Cu3(PO4)2, CuO, Cu2O, Cu(OH)2, CuCl, Cu(CH3COO)2, Al(H2PO4)3, TiN, Ti2N, AlN, Si3N4, TaN, LaN, preferably the combination of Cu3N, Al(H2PO4)3, TiN;

[0035] In some embodiments, the mass of the dopant in step (2) accounts for 0.01% - 6% of the total mass of the lithium source, fluorine-doped modified lithium borate and zirconium source, preferably 0.04% - 4%, more preferably 0.06% - 3%, wherein the mass ratio of the lithium source, fluorine-doped modified lithium borate, and zirconium source is 1 - 10:1 - 3:1 - 3, preferably 2 - 8:1 - 2:1 - 2, more preferably 2 - 6:1:1.

[0036] In some embodiments, the mass ratio of the fluorine-doped modified lithium borate to the ZrO2 or Zr 0.92 O2Y 0.08 or Zr 0.97 O2Y 0.03 zirconium source is 1 - 3:1 - 3, preferably 1 - 2:1 - 2, more preferably 1:1;

[0037] Preferably, ZrO2 or Zr 0.92 O2Y 0.08 or Zr 0.97 O2Y 0.03The purity of the zirconium source is ≥99.9%, and its D50 particle size is 0.02 μm to 2.0 μm, preferably 0.02 μm to 1.5 μm, more preferably 0.04 μm to 1.0 μm;

[0038] In some embodiments, the mass ratio of the fluorine-doped modified lithium borate to the zirconium source of Zr(CO3)2 or Zr(OH)4 in step (2) is 1 to 3:1 to 3, preferably 1 to 2:1 to 2, more preferably 1:1;

[0039] Preferably, the purity of the zirconium source of Zr(CO3)2 or Zr(OH)4 is ≥99.5%, and its D50 particle size is 0.04 μm to 3.0 μm, preferably 0.04 μm to 2.0 μm, more preferably 0.4 μm to 1.5 μm;

[0040] In some embodiments, the mass ratio of the fluorine-doped modified lithium borate to the lithium source of Li2O or Li2CO3 or LiOH·H2O in step (2) is 1 to 3:1 to 10, preferably 1 to 2:2 to 8, more preferably 1:2 to 6;

[0041] Preferably, the purity of Li2O is ≥99.9%, and its D50 particle size is 1.0 μm to 10.0 μm, preferably 2.0 μm to 8.0 μm, more preferably 2.0 μm to 5.0 μm;

[0042] Preferably, the purity of Li2CO3 is ≥99.5%, and its D50 particle size is 1.0 μm to 10.0 μm, preferably 2.0 μm to 8.0 μm, more preferably 2.0 μm to 5.0 μm;

[0043] Preferably, the purity of LiOH·H2O is ≥99.0%, and its D50 particle size is 1.0 μm to 10.0 μm, preferably 2.0 μm to 8.0 μm, more preferably 2.0 μm to 5.0 μm;

[0044] In some embodiments, the mass ratio of the total mass of the lithium source, the fluorine-doped modified lithium borate and the zirconium source to the mass of Cu3N in step (2) is 1.0:0.0001 to 0.02, preferably 1:0.0004 to 0.018, more preferably 1:0.0006 to 0.016;

[0045] Preferably, the purity of Cu3N is ≥99.9%, and its D50 particle size is 0.04 μm to 5 μm, preferably 0.1 μm to 4.0 μm, more preferably 0.4 μm to 3.0 μm;

[0046] In some embodiments, the mass ratio of the total mass of the lithium source, the fluorine-doped modified lithium borate and the zirconium source to the mass of TiN in step (2) is 1.0:0.0001 to 0.02, preferably 1:0.0004 to 0.016, more preferably 1:0.0006 to 0.013;

[0047] Preferably, the purity of TiN is ≥99.9%, its D50 particle size is 0.05 μm to 4.0 μm, preferably 0.1 μm to 3.0 μm, more preferably 0.3 μm to 3.0 μm;

[0048] In some embodiments, the mass ratio of the total mass of the lithium source, fluorine-doped modified lithium borate, and zirconium source to the mass of the Al(H2PO4)3 in step (2) is 1.0:0.0001 to 0.02, preferably 1:0.0004 to 0.016, more preferably 1:0.0006 to 0.013;

[0049] Preferably, the purity of Al(H2PO4)3 is ≥99.9%, its D50 particle size is 0.04 μm to 6 μm, preferably 0.1 μm to 5 μm, more preferably 0.4 μm to 3 μm;

[0050] In some embodiments, the mixing ball milling speed in step (2) is 200 to 2500 rpm, preferably 300 to 2200 rpm, more preferably 1000 to 2200 rpm;

[0051] In some embodiments, the mixing ball milling time in step (2) is 1.0 to 10.0 h, preferably 2.0 to 8.0 h, more preferably 3.0 to 6.0 h;

[0052] In some embodiments, the ball-to-material ratio of the mixing ball milling in step (2) is 3 to 20:1, preferably 4 to 18:1, more preferably 5 to 12:1;

[0053] In some embodiments, the particle size of the mixture containing lithium zirconium borate after the mixing ball milling in step (2) is 0.7 to 1.0 μm.

[0054] Step (3):

[0055] The product obtained in step (2) is loaded into a corundum crucible, pressed into tablets, and then transferred to a primary sintering device, where it is subjected to high-temperature primary sintering in an inert atmosphere with a slightly positive or slightly negative pressure, and then obtained the doped and modified lithium zirconium borate product after air flow crushing, sieving, and demagnetization.

[0056] In some embodiments, the pressing pressure in step (3) is 18 to 36 MPa, preferably 20 to 34 MPa, more preferably 24 to 32 MPa;

[0057] In some embodiments, the pressing time in step (3) is 1 to 20 s, preferably 2 to 15 s, more preferably 3 to 10 s;

[0058] In some embodiments, the primary sintering device in step (3) is a vacuum box-type atmosphere furnace, a vacuum tube furnace, or an atmosphere roller hearth kiln, preferably a vacuum box-type atmosphere furnace or an atmosphere roller hearth kiln;

[0059] In some embodiments, the isothermal holding time for the first sintering in step (3) is 2 to 32 h, preferably 3 to 24 h, and more preferably 3 to 18 h;

[0060] In some embodiments, the isothermal holding temperature for the first sintering in step (3) is 200 to 2400 °C, preferably 400 to 1800 °C, and more preferably 600 to 1500 °C;

[0061] In some embodiments, the inert atmosphere in step (3) is one of argon and nitrogen.

[0062] In some embodiments, the slightly positive pressure in step (3) is 10 to 200 Pa, preferably 15 to 120 Pa, and more preferably 20 to 100 Pa;

[0063] In some embodiments, the slightly negative pressure in step (3) is -15 to -180 Pa, preferably -18 to -120 Pa, and more preferably -25 to -100 Pa.

[0064] In some embodiments, the particle size of the doped and modified lithium zirconium borate obtained in step (3) is 300 nm - 1.0 μm.

[0065] Step (4):

[0066] The doped and modified lithium zirconium borate in step (3) is dry-mixed and ball-milled with a coating agent, then loaded into a corundum crucible, pressed into tablets, and transferred to a secondary sintering device. High-temperature secondary sintering is carried out in an inert atmosphere with slightly positive or slightly negative pressure, and then the finished product of coated and modified lithium zirconium borate is obtained after crushing, grinding or ball-milling, sieving, and demagnetization.

[0067] In some embodiments, the mass ratio of the doped and modified lithium zirconium borate to the coating agent (based on the total amount of the coating agent) is 1:0.0001 to 0.040, preferably 1:0.0004 to 0.036, and more preferably 1:0.0006 to 0.032;

[0068] In some embodiments, the coating agent in step (4) is one or a combination of two or more of Cu3N, Cu3(PO4)2, CuO, Cu2O, Cu(OH)2, CuCl, Cu(CH3COO)2, Al(H2PO4)3, TiN, Ti2N, AlN, Si3N4, TaN, LaN, C2H3O2Li, and LiOH;

[0069] Preferably, a combination of AlN, TaN, LaN, and C2H3O2Li.

[0070] In some embodiments, the mass ratio of the doped and modified lithium zirconium borate to the C2H3O2Li in step (4) is 1:0.0001 - 0.020, preferably 1:0.0002 - 0.018, more preferably 1:0.0003 - 0.016;

[0071] Preferably, the purity of the coating agent anhydrous C2H3O2Li is ≥99.0%, and its D50 particle size is 20nm - 100nm;

[0072] In some embodiments, the mass ratio of the doped and modified lithium zirconium borate to the AlN in step (4) is 1:0.0002 - 0.012, preferably 1:0.0006 - 0.01, more preferably 1:0.001 - 0.01;

[0073] Preferably, the purity of the coating agent AlN is ≥99.0%, and its D50 particle size is 200nm - 500nm;

[0074] In some embodiments, the mass ratio of the doped and modified lithium zirconium borate to the TaN in step (4) is 1:0.0002 - 0.012, preferably 1:0.0006 - 0.01, more preferably 1:0.001 - 0.01;

[0075] Preferably, the purity of the coating agent TaN is ≥99.0%, and its D50 particle size is 200nm - 500nm;

[0076] In some embodiments, the mass ratio of the doped and modified lithium zirconium borate to the LaN in step (4) is 1:0.0002 - 0.012, preferably 1:0.0006 - 0.01, more preferably 1:0.001 - 0.01;

[0077] Preferably, the purity of the coating agent LaN is ≥99.5%, and its D50 particle size is 200nm - 500nm;

[0078] In some embodiments, the tableting pressure in step (4) is 10 - 20MPa, preferably 12 - 18MPa, more preferably 14 - 16MPa;

[0079] In some embodiments, the tableting time in step (4) is 1 - 10s, preferably 2 - 8s, more preferably 3 - 6s;

[0080] In some embodiments, the secondary sintering equipment in step (4) is a vacuum box - type atmosphere furnace, a vacuum tube furnace, or an atmosphere roller hearth kiln, preferably a vacuum box - type atmosphere furnace or an atmosphere roller hearth kiln;

[0081] In some embodiments, the isothermal time of the secondary sintering in step (4) is 1 to 10 h, preferably 1.5 to 8 h, more preferably 2 to 6 h;

[0082] In some embodiments, the isothermal temperature of the secondary sintering in step (4) is 100 to 1100 °C, preferably 150 to 1000 °C, more preferably 200 to 980 °C;

[0083] In some embodiments, the inert atmosphere in step (4) is one of argon and nitrogen.

[0084] In some embodiments, the slightly positive pressure in step (4) is 10 to 150 Pa, preferably 15 to 100 Pa, more preferably 20 to 80 Pa;

[0085] In some embodiments, the slightly negative pressure in step (4) is -15 to -150 Pa, preferably -18 to -100 Pa, more preferably -25 to -80 Pa;

[0086] In some embodiments, the particle size of the modified oxide solid electrolyte material obtained in step (4) is 50 nm to 900 nm.

[0087] In a second aspect, the present invention provides a modified oxide solid electrolyte material prepared by the above preparation method.

[0088] The lithium zirconium borate (LZBO) solid electrolyte prepared by the method has comprehensive application performances such as electronic grade functional materials, modified raw materials for cathode materials, diaphragm modification, electrode slurries, electrolyte films, etc.

[0089] In a third aspect, the present invention provides an application of the modified oxide solid electrolyte material in the preparation of secondary batteries.

[0090] Applications in the technical fields of all-solid-state batteries and semi-solid-state batteries; preferably, the secondary battery is a lithium-ion battery.

[0091] Technical effects:

[0092] The method of the present invention improves the voltage stability and electrode compatibility of the synthesized electrolyte by modifying lithium borate, thereby enhancing the overall performance and safety of the battery;

[0093] The method of the present invention improves the performance of the solid electrolyte, increases the ionic conductivity, and reduces the contact resistance by innovating the raw material combination, effectively enhancing its comprehensive performance;

[0094] The method of the present invention significantly improves the purity of the product, reduces the reaction temperature, and reduces the energy consumption by introducing specific additives;

[0095] The method of the present invention further improves the performance of lithium zirconium borate (LZBO) through secondary high-temperature modification.

[0096] The present invention has been described in detail above, but the above embodiments are essentially illustrative only and are not intended to limit the present invention. In addition, the present invention is not limited by any theory described in the foregoing prior art or the summary of the invention or the following examples. Description of the Drawings

[0097] Figure 1 It is a process flow chart of the preparation method of the modified oxide solid electrolyte material of the present invention;

[0098] Figure 2 It is a SEM image of the solid electrolyte prepared in Example 2 of the present invention. Detailed Description of the Invention

[0099] The present invention will be further described below in conjunction with embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed by the present invention.

[0100] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are all conventional raw materials, reagents, methods in the art.

[0101] In the following examples of the present invention, lithium metaborate, lithium oxide, lithium boride, lithium fluoride, zirconium source, lithium source, dopant, and coating agent can be purchased as raw materials of the same required specifications in the market, or can be prepared according to conventional synthesis methods.

[0102] Example 1

[0103] As Figure 1 shown in the flow chart, a modified oxide solid electrolyte material and a preparation method thereof according to this example include the following steps:

[0104] (1) First, weigh 50 g each of BLiO2, Li2O, and B4Li2O7 (D50: 2.5 μm) and 0.75 g of LiF (D50: 1.5 μm) powder materials, put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 8:1, then ball mill at 1200 rpm for 4.0 h. After ball milling, the D50 range of the particle size is 0.8 - 1.2 μm, and then transfer it to a microwave catalytic synthesizer, introduce argon, and heat it to 600 °C at a rate of 5 °C / min and keep it at a constant temperature for 2.0 h;

[0105] (2) Weigh Li2O (D50: 2.5 μm), Zr 0.97 O2Y 0.03(D50: 2.0 μm), 100 g, 50 g, 50 g, 1.04 g, 0.64 g, and 0.52 g of lithium borate (D50: 1.1 μm), Cu3N (D50: 1.0 μm), TiN (D50: 1.0 μm), and Al(H2PO4)3 (D50: 1.0 μm) powders obtained in step (1) were put into a high-energy mixing ball mill at a ball-to-material ratio of 10:1 and ball-milled at 2000 rpm for 5.0 h. After ball milling, the D50 particle size range was 0.7 - 1.0 μm;

[0106] (3) The material obtained by mixing and ball milling in step (2) was loaded into a corundum crucible and pressed for 8 s at 28 MPa, then transferred to a vacuum box-type atmosphere furnace and heated to 1200 °C at a rate of 5 °C / min under slightly positive pressure of dry air and held at a constant temperature for 1.0 h, then cooled to 842 °C at a rate of 5 °C / min and held at a constant temperature for 4.0 h, then cooled to 280 °C at a rate of 5 °C / min and held at a constant temperature for 1.0 h, and then cooled and put into a jet mill to be crushed to 500 nm - 1.2 μm, and finally, after sieving and magnetic separation, the doped and modified lithium zirconium borate (LZBO) matrix was obtained;

[0107] (4) 120 g, 0.215 g, 0.480 g, 0.432 g, and 0.240 g of AlN (D50: 300 nm), TaN (D50: 300 nm), LaN (D50: 300 nm), and C2H3O2Li (D50: 80 nm) were weighed respectively with the doped and modified lithium zirconium borate (LZBO) matrix obtained in step (3). They were put into a high-energy mixing ball mill at a ball-to-material ratio of 10:1 and ball-milled at 1800 rpm for 4.0 h, then loaded into a corundum crucible and pressed for 5 s at 15 MPa, then transferred to a vacuum box-type atmosphere furnace and heated to 460 °C at a rate of 5 °C / min under slightly positive pressure of dry air and held at a constant temperature for 1.0 h, then heated to 796 °C at a rate of 5 °C / min and held at a constant temperature for 3.0 h, and then cooled and put into a jet mill to be crushed to 50 nm - 900 nm, and finally, after sieving and magnetic separation, the coated and modified lithium zirconium borate (LZBO) product was obtained.

[0108] Example 2

[0109] As Figure 1 shown in the flowchart, a modified oxide solid electrolyte material and its preparation method in this example include the following steps:

[0110] (1) First, weigh 50 g each of BLiO2, Li2O, and B4Li2O7 (D50: 2.5 μm), and 0.525 g of LiF (D50: 1.5 μm) powder materials. Put them into a high-energy hybrid ball milling tank at a ball-to-material ratio of 8:1, and then ball mill at 1200 rpm for 4.0 h. After ball milling, the D50 range of the particle size is 0.8 - 1.2 μm. Then transfer it to a microwave catalytic synthesizer, introduce argon gas, and heat it to 600 °C at a rate of 5 °C / min and keep it at a constant temperature for 2.5 h;

[0111] (2) Weigh 100 g of Li2CO3 (D50: 2.5 μm), 0.92 ZrO2Y 0.08 (D50: 2.0 μm), 50 g of lithium borate obtained in step (1) (D50: 1.1 μm), 0.76 g of Cu3N (D50: 1.0 μm), 0.72 g of TiN (D50: 1.0 μm), and 0.48 g of Al(H2PO4)3 (D50: 1.0 μm) powder materials. Put them into a high-energy hybrid ball milling tank at a ball-to-material ratio of 10:1 and ball mill at 2000 rpm for 4.8 h. After ball milling, the D50 particle size range is 0.7 - 1.0 μm;

[0112] (3) Put the material obtained by hybrid ball milling in step (2) into a corundum crucible, press it for 8 s at 28 MPa, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under slightly positive pressure dry air and keep it at a constant temperature for 1.0 h, then cool it to 842 °C at a rate of 5 °C / min and keep it at a constant temperature for 4.2 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature for 1.0 h, and then cool it and put it into a jet mill to crush it to 500 nm - 1.2 μm. Finally, obtain the doped and modified lithium zirconium borate (LZBO) matrix after sieving and magnetic separation;

[0113] (4) Weigh 120 g of AlN (D50: 300 nm), 0.264 g of TaN (D50: 300 nm), 0.504 g of LaN (D50: 300 nm), and 0.408 g of C2H3O2Li (D50: 80 nm) and 0.240 g of the doped and modified lithium zirconium borate (LZBO) matrix obtained in step (3). Put them into a high-energy hybrid ball milling tank at a ball-to-material ratio of 10:1 and ball mill at 1800 rpm for 4.0 h. Then put it into a corundum crucible and press it for 5 s at 15 MPa, and then transfer it to a vacuum box-type atmosphere furnace, heat it to 460 °C at a rate of 5 °C / min under slightly positive pressure dry air and keep it at a constant temperature for 1.0 h, then heat it to 796 °C at a rate of 5 °C / min and keep it at a constant temperature for 3.5 h, and then cool it and put it into a jet mill to crush it to 50 nm - 900 nm. Finally, obtain the coated and modified lithium zirconium borate (LZBO) finished product after sieving and magnetic separation.

[0114] Example 3

[0115] As Figure 1 shown in the flowchart, for the modified oxide solid electrolyte material and its preparation method in this embodiment, the following steps are included:

[0116] (1) First, weigh 50 g (D50: 2.5 μm) of BLiO2, Li2O, and B4Li2O7 each, and 0.525 g (D50: 1.5 μm) of LiF powder. Put them into a high-energy mixing ball mill tank at a ball-to-material ratio of 8:1, then ball mill at 1200 rpm for 4.0 h. After ball milling, the D50 particle size range is 0.8 - 1.2 μm. Then transfer it to a microwave catalytic synthesizer, introduce argon, and heat it to 600 °C at a rate of 5 °C / min and keep it at a constant temperature for 2.5 h;

[0117] (2) Weigh 150 g, 50 g, 50 g, 0.76 g, 0.72 g, and 0.48 g of LiOH·H2O (D50: 2.5 μm), Zr 0.92 O2Y 0.08 (D50: 2.0 μm), lithium borate obtained in step (1) (D50: 1.1 μm), Cu3N (D50: 1.0 μm), TiN (D50: 1.0 μm), and Al(H2PO4)3 (D50: 1.0 μm) powder respectively. Put them into a high-energy mixing ball mill tank at a ball-to-material ratio of 10:1 and ball mill at 2000 rpm for 4.8 h. After ball milling, the D50 particle size range is 0.7 - 1.0 μm;

[0118] (3) Put the material obtained by mixing and ball milling in step (2) into a corundum crucible, press it at 28 MPa for 8 s, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under slightly negative pressure of dry air and keep it at a constant temperature for 1.0 h, then cool it to 842 °C at a rate of 5 °C / min and keep it at a constant temperature for 4.2 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature for 1.0 h. Then, after cooling, put it into an air classifier to crush it to 500 nm - 1.2 μm, and finally, after sieving and magnetic separation, obtain the doped and modified lithium zirconium borate (LZBO) matrix;

[0119] (4) Weigh 120 g, 0.264 g, 0.504 g, 0.408 g, and 0.240 g of the lithium zirconium borate (LZBO) matrix obtained by doping and modification in step (3), AlN (D50: 300 nm), TaN (D50: 300 nm), LaN (D50: 300 nm), and C2H3O2Li (D50: 80 nm) respectively, and put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 10:1. Ball mill at 1800 rpm for 4.0 h, then load them into a corundum crucible and press them for 5 s at 15 MPa, then transfer them into a vacuum box-type atmosphere furnace and heat them to 460 °C at a rate of 5 °C / min under slightly negative pressure of dry air and keep them at a constant temperature for 1.0 h. Then, heat them to 796 °C at a rate of 5 °C / min and keep them at a constant temperature for 3.5 h. After cooling, put them into a jet mill to crush them to 50 nm - 900 nm, and finally obtain the finished product of coated and modified lithium zirconium borate (LZBO) by sieving and magnetic separation.

[0120] Example 4

[0121] As Figure 1 shown in the flowchart, the modified oxide solid electrolyte material and its preparation method described in this example include the following steps:

[0122] (1) First, weigh 50 g (D50: 2.5 μm) of BLiO2, 50 g of Li2O, 50 g of B4Li2O7, and 1.65 g (D50: 1.5 μm) of LiF powder materials. Put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 8:1, and then ball mill at 1200 rpm for 4.0 h. After ball milling, the D50 particle size range is 0.8 - 1.2 μm. Then transfer them into a microwave catalytic synthesizer, introduce argon, and heat them to 600 °C at a rate of 5 °C / min and keep them at a constant temperature for 2.5 h;

[0123] (2) Weigh 100 g of Li2CO3 (D50: 2.5 μm), 50 g of Zr(CO3)2 (D50: 2.0 μm), 50 g of lithium borate (D50: 1.1 μm) obtained in step (1), 1.60 g of Cu3N (D50: 1.0 μm), 0.80 g of TiN (D50: 1.0 μm), and 0.64 g of Al(H2PO4)3 (D50: 1.0 μm) powder materials. Put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 10:1, and ball mill at 2000 rpm for 4.8 h. After ball milling, the D50 particle size range is 0.7 - 1.0 μm;

[0124] (3) Load the material obtained by the hybrid ball milling in step (2) into a corundum crucible, press it for 8 s at 28 MPa, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under slightly negative pressure of dry air, hold it at a constant temperature for 1.0 h, then cool it to 842 °C at a rate of 5 °C / min and hold it at a constant temperature for 4.2 h, then cool it to 280 °C at a rate of 5 °C / min and hold it at a constant temperature for 1.0 h, then cool it and put it into a jet mill to crush it to 500 nm - 1.2 μm, and finally obtain the doped and modified lithium zirconium borate (LZBO) matrix by sieving and removing magnetic substances;

[0125] (4) Weigh 120 g, 0.216 g, 0.576 g, 0.60 g, and 0.288 g of the lithium zirconium borate (LZBO) matrix obtained by doping and modification in step (3), AlN (D50: 300 nm), TaN (D50: 300 nm), LaN (D50: 300 nm), and C2H3O2Li (D50: 80 nm) respectively, put them into a high-energy hybrid ball milling tank according to a ball-to-material ratio of 10:1, ball mill them at 1800 rpm for 4.0 h, then load them into a corundum crucible and press them for 5 s at 15 MPa, then transfer them to a vacuum box-type atmosphere furnace and heat them to 460 °C at a rate of 5 °C / min under slightly negative pressure of dry air, hold them at a constant temperature for 1.0 h, then heat them to 796 °C at a rate of 5 °C / min and hold them at a constant temperature for 3.5 h, then cool them and put them into a jet mill to crush them to 50 nm - 900 nm, and finally obtain the coated and modified lithium zirconium borate (LZBO) finished product by sieving and removing magnetic substances.

[0126] Example 5

[0127] As Figure 1 shown in the flowchart, a modified oxide solid electrolyte material and its preparation method according to this example include the following steps:

[0128] (1) First, weigh 50 g (D50: 2.5 μm) of BLiO2, Li2O, and B4Li2O7 respectively, and 1.65 g (D50: 1.5 μm) of LiF powder, put them into a high-energy hybrid ball milling tank according to a ball-to-material ratio of 8:1, then ball mill them at 1200 rpm for 4.0 h. After ball milling, the particle size in the D50 range is 0.8 - 1.2 μm, and then transfer them to a microwave catalytic synthesizer, introduce argon, and heat them to 600 °C at a rate of 5 °C / min and hold them at a constant temperature for 2.5 h;

[0129] (2) Weigh 100 g of Li2CO3 (D50: 2.5 μm), 50 g of Zr(OH)4 (D50: 2.0 μm), 50 g of lithium borate obtained in step (1) (D50: 1.1 μm), 1.60 g of Cu3N (D50: 1.0 μm), 0.80 g of TiN (D50: 1.0 μm), and 0.64 g of Al(H2PO4)3 (D50: 1.0 μm). Put them into a high-energy mixing ball mill tank at a ball-to-material ratio of 10:1 and ball mill at 2000 rpm for 4.8 h. After ball milling, the D50 particle size range is 0.7 - 1.0 μm;

[0130] (3) Load the material obtained by mixing and ball milling in step (2) into a corundum crucible, press it at 28 MPa for 8 s, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under slightly positive pressure of dry air, keep it at a constant temperature for 1.0 h, then cool it to 842 °C at a rate of 5 °C / min and keep it at a constant temperature for 4.2 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature for 1.0 h, and then after cooling, put it into a jet mill to crush it to 500 nm - 1.2 μm, and finally obtain the doped and modified lithium zirconium borate (LZBO) matrix by sieving and removing magnetic substances;

[0131] (4) Weigh 120 g of AlN (D50: 300 nm), 0.216 g of TaN (D50: 300 nm), 0.576 g of LaN (D50: 300 nm), 0.60 g of C2H3O2Li (D50: 80 nm), and 0.288 g of the doped and modified lithium zirconium borate (LZBO) matrix obtained in step (3). Put them into a high-energy mixing ball mill tank at a ball-to-material ratio of 10:1 and ball mill at 1800 rpm for 4.0 h, then load it into a corundum crucible and press it at 15 MPa for 5 s, then transfer it to a vacuum box-type atmosphere furnace, heat it to 460 °C at a rate of 5 °C / min under slightly positive pressure of dry air, keep it at a constant temperature for 1.0 h, then heat it to 796 °C at a rate of 5 °C / min and keep it at a constant temperature for 3.5 h, and then after cooling and crushing, put it into a jet mill to crush it to 50 nm - 900 nm, and finally obtain the coated and modified lithium zirconium borate (LZBO) finished product by sieving and removing magnetic substances.

[0132] Example 6

[0133] As Figure 1 shown in the flow chart, a modified oxide solid electrolyte material and its preparation method according to this example include the following steps:

[0134] (1) First, weigh 50 g each of BLiO2, Li2O, and B4Li2O7 (D50: 2.5 μm), 1.65 g of LiF (D50: 1.5 μm) powder materials, and put them into a high-energy hybrid ball milling tank at a ball-to-material ratio of 8:1. Then, ball mill at 1200 rpm for 4.0 h. After ball milling, the D50 particle size range is 0.8 - 1.2 μm. Then transfer it to a microwave catalytic synthesizer, introduce argon gas, and heat it to 600 °C at a rate of 5 °C / min and keep it at a constant temperature for 2.5 h;

[0135] (2) Weigh 100 g of Li2CO3 (D50: 2.5 μm), 50 g of ZrO2 (D50: 2.0 μm), 50 g of lithium borate obtained in step (1) (D50: 1.1 μm), 1.60 g of Cu3N (D50: 1.0 μm), 0.80 g of TiN (D50: 1.0 μm), and 0.64 g of Al(H2PO4)3 (D50: 1.0 μm) powder materials. Put them into a high-energy hybrid ball milling tank at a ball-to-material ratio of 10:1 and ball mill at 2000 rpm for 4.8 h. After ball milling, the D50 particle size range is 0.7 - 1.0 μm;

[0136] (3) Put the material obtained by mixing and ball milling in step (2) into a corundum crucible, press it for 8 s at 28 MPa, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under slightly negative pressure of dry air and keep it at a constant temperature for 1.0 h. Then cool it to 842 °C at a rate of 5 °C / min and keep it at a constant temperature for 4.2 h. Then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature for 1.0 h. Then, after cooling, put it into a jet mill to crush it to 500 nm - 1.2 μm. Finally, obtain the doped and modified lithium zirconium borate (LZBO) matrix after sieving and magnetic separation;

[0137] (4) Weigh 120 g of AlN (D50: 300 nm), 0.216 g of TaN (D50: 300 nm), 0.576 g of LaN (D50: 300 nm), 0.60 g of C2H3O2Li (D50: 80 nm), and 0.288 g of the doped and modified lithium zirconium borate (LZBO) matrix obtained in step (3). Put them into a high-energy hybrid ball milling tank at a ball-to-material ratio of 10:1 and ball mill at 1800 rpm for 4.0 h. Then put it into a corundum crucible and press it for 5 s at 15 MPa. Then transfer it to a vacuum box-type atmosphere furnace, heat it to 460 °C at a rate of 5 °C / min under slightly negative pressure of dry air and keep it at a constant temperature for 1.0 h. Then heat it to 796 °C at a rate of 5 °C / min and keep it at a constant temperature for 3.5 h. Then, after cooling, put it into a jet mill to crush it to 50 nm - 900 nm. Finally, obtain the coated and modified lithium zirconium borate (LZBO) finished product after sieving and magnetic separation.

[0138] Comparative Example 1

[0139] The difference from Example 2 is that only one high-temperature synthesis is adopted, and doping and coating are not carried out, including the following steps:

[0140] (1) The same as in Example 2;

[0141] (2) Weigh 100 g, 50 g, and 50 g of Li2CO3 (D50: 2.5 μm), Zr 0.92 O2Y 0.08 (D50: 2.0 μm), and the lithium borate powder (D50: 1.1 μm) obtained in step (1) respectively. Put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 10:1, ball mill at 2000 rpm for 5.0 h, and take a sample to test D50 = 1.2 μm with a laser particle size analyzer;

[0142] (3) Put the material obtained by mixing and ball milling in step (2) into a corundum crucible, press it into tablets at 28 MPa for 8 s, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under dry air and keep it at a constant temperature for 1.0 h, then cool it to 1020 °C at a rate of 5 °C / min and keep it at a constant temperature for 6.0 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature for 1.0 h, and then break it into particles with a particle size of 50 nm - 900 nm by a jet mill after cooling, and finally obtain lithium zirconium borate (LZBO) by sieving and removing magnetic substances.

[0143] Comparative Example 2

[0144] The difference from Example 2 is that no doping modification of relevant elements is carried out, including the following steps:

[0145] (1) The same as in Example 2;

[0146] (2) Weigh 100 g, 50 g, and 50 g of Li2CO3 (D50: 2.5 μm), Zr 0.92 O2Y 0.08 (D50: 2.0 μm), and the lithium borate powder (D50: 1.1 μm) obtained in step (1) respectively. Put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 10:1, ball mill at 2000 rpm for 5.0 h, and take a sample to test D50 = 1.2 μm with a laser particle size analyzer;

[0147] (3) Put the material obtained by mixing and ball milling in step (2) into a corundum crucible, press it into tablets at 28 MPa for 8 s, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under dry air and keep it at a constant temperature for 1.0 h, then cool it to 1020 °C at a rate of 5 °C / min and keep it at a constant temperature for 6.0 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature for 1.0 h, and then break it into particles with a particle size of 500 nm - 1.2 μm by a jet mill after cooling, and finally obtain the lithium zirconium borate (LZBO) matrix;

[0148] (4) The same as in Example 2.

[0149] Comparative Example 3

[0150] The difference from Example 2 is that coating and secondary sintering are not carried out, including the following steps:

[0151] (1) and (2) are the same as in Example 2;

[0152] (3) Load the material obtained by mixing and ball milling in step (2) into a corundum crucible, press it at 28 MPa for 8 s, transfer it to a vacuum box-type atmosphere furnace, heat it to 1200 °C at a rate of 5 °C / min under dry air, keep it at a constant temperature of 1.0 h, then cool it to 1020 °C at a rate of 5 °C / min and keep it at a constant temperature of 6.0 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature of 1.0 h, then after cooling, put it into a jet mill to crush it to 50 nm - 900 nm, and finally obtain lithium zirconium borate (LZBO) through sieving and magnetic separation.

[0153] Comparative Example 4

[0154] The difference from Example 2 is that lithium zirconium borate (LZBO) is synthesized by a one-step method, and no doping and coating are carried out, including the following steps:

[0155] Weigh 120 g, 60 g, 20 g, 20 g, and 20 g of Li2CO3 (D50: 2.5 μm), Zr 0.92 O2Y 0.08 (D50: 2.0 μm), BLiO2 (D50: 2.5 μm), Li2O (D50: 2.5 μm), and B4Li2O7 (D50: 2.5 μm) respectively, put them into a high-energy mixing ball mill tank according to a ball-to-material ratio of 10:1, and ball mill at 2000 rpm for 12.0 h; then load the material obtained by mixing and ball milling into a corundum crucible, press it at 28 MPa for 8 s, transfer it to a vacuum box-type atmosphere furnace, heat it to 1400 °C at a rate of 5 °C / min under dry air, keep it at a constant temperature of 1.0 h, then cool it to 1100 °C at a rate of 5 °C / min and keep it at a constant temperature of 12.0 h, then cool it to 280 °C at a rate of 5 °C / min and keep it at a constant temperature of 1.0 h, then after cooling, put it into a jet mill to crush it to 50 nm - 900 nm, and finally obtain lithium zirconium borate (LZBO) through sieving and magnetic separation.

[0156] Experimental Example

[0157] 1. Physical and Chemical Property Tests

[0158] The prepared oxide solid electrolytes of the above examples and comparative examples were tested for physical and chemical indexes such as particle size, tapped density, purity, moisture, residual alkali, and ionic conductivity. The results are shown in Table 1:

[0159] Table 1 Physical and Chemical Index Test Results of Each Example and Comparative Example

[0160] Particle size D50 (nm) <![CDATA[Tap density g / cm 3 > Purity % Moisture ppm Residual alkali ppm Ionic conductivity S / cm Appearance color Particle morphology Example 1 315 1.58 99.86 216 5846 <![CDATA[6.84×10 -4 > White Single-particle spherical and quasi-spherical Example 2 294 1.63 99.85 194 5630 <![CDATA[8.92×10 -4 > White Single-particle spherical and quasi-spherical Example 3 306 1.59 99.87 191 5321 <![CDATA[7.31×10 -4 > White Single-particle spherical and quasi-spherical Example 4 328 1.61 99.84 211 5914 <![CDATA[5.69×10 -4 > White Single-particle spherical and quasi-spherical Example 5 319 1.62 99.86 184 5438 <![CDATA[5.71×10 -4 > White Single-particle spherical and quasi-spherical Example 6 330 1.57 99.83 168 5710 <![CDATA[6.18×10 -4 > White Single-particle spherical and quasi-spherical Comparative Example 1 356 1.32 99.62 243 7696 <![CDATA[2.58×10 -4 > White Single-particle spherical and quasi-spherical Comparative Example 2 364 1.41 99.63 226 7543 <![CDATA[3.06×10 -4 > White Single-particle spherical and quasi-spherical Comparative Example 3 378 1.43 99.61 224 7614 <![CDATA[3.14×10 -4 > White Single-particle spherical and quasi-spherical Comparative Example 4 362 1.26 99.48 231 9108 <![CDATA[1.46×10 -4 > White Single-particle spherical and quasi-spherical

[0161] It can be seen from the test data in Table 1 that the ionic conductivity of the LZBO oxide solid electrolyte powder after being doped with a certain amount of Cu / Ti / Al / P / N and synergistically surface-doped and coated with Ta / Al / La / Li is significantly improved. The addition amounts of different modifying elements and process parameters such as different raw materials, heat preservation temperature, and cooling rate all play a role in the improvement effect of the ionic conductivity and there are certain differences.

[0162] 2. Rate performance test

[0163] The rate performance of the oxide solid electrolytes prepared in the above examples and comparative examples was evaluated by the following method.

[0164] A solid-state battery with LiNi0.65Co0.2Mn0.15O2 as the positive electrode and metallic lithium as the negative electrode was fabricated to evaluate the rate performance and cycling performance of the oxide solid electrolyte. The specific operation method is as follows:

[0165] 1) LiNi0.65Co0.2Mn0.15O2, binder PVDF (polyvinylidene fluoride), CNT, conductive agent Super P, and solid electrolyte (LZBO) were mixed in a mass ratio of 96.5:1.2:0.6:0.7:1.0, and an appropriate amount of solvent NMP (N-methylpyrrolidone) was added and stirred to prepare a positive electrode slurry (solid content 73%). It was coated on aluminum foil and dried at 105 °C, and then cut into circular pieces with a diameter of 10 mm as the positive electrode sheets.

[0166] 2) The solid electrolyte LZBO (75%) and PEO (25%) were mixed and ground for 3 h, and then hot-pressed at 95 °C / 6.8 Mpa to obtain a solid electrolyte membrane with a thickness of about 60 μm.

[0167] 3) Assembled into a CR2032 coin-type battery in the order of positive electrode sheet - solid electrolyte membrane - lithium foil for battery rate and cycling tests.

[0168] The working voltage range of the above lithium secondary battery was set to 3.0 V to 4.40 V, and it was charged at a constant current of 0.1C to 4.40 V and then at a constant voltage until the cut-off current of 0.01C; then discharged at currents of 0.1C, 0.2C, 0.5C, 1.0C, and 2.0C to 3.0 V respectively to obtain the specific capacity per gram of the material at discharge rates of 0.1C, 0.2C, 0.5C, 1.0C, and 2.0C, and then the charge-discharge cycle test was carried out at 2.0C. The test results are shown in Table 2:

[0169] Table 2 Rate test results of each example and comparative example

[0170]

[0171] As can be seen from the test data in Table 2, after the LZBO oxide solid electrolyte powder is doped with a certain amount of Cu / Ti / Al / P / N in the bulk and modified by Ta / Al / La / Li co-surface doping and coating, the rate and cycle performance of the LZBO oxide solid electrolyte are significantly improved compared with the comparative example. The addition amounts of different modifying elements and process parameters such as different raw materials, holding temperature, and cooling rate all play a role in the improvement effect of ionic conductivity and there are certain differences.

[0172] It can be seen that lithium zirconium borate (LZBO) prepared under the preparation method and process system of this oxide solid electrolyte material can meet the relevant performance indicators of similar oxide solid electrolytes.

[0173] The technical solutions of the above embodiments are only preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solutions of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: within the scope of the spirit and essence defined by the claims of the present invention, the technical solutions described in the foregoing embodiments can be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements still fall within the scope defined by the claims of the present invention.

Claims

1. A method for preparing a modified oxide solid electrolyte material, characterized in that: The following steps are involved: (1) mixing BLiO2, Li2O, B4Li2O7 and LiF and ball-milling to obtain initial lithium borate, and then pre-sintering to obtain fluorine-doped modified lithium borate; (2) dry-mixing and ball-milling the fluorine-doped lithium borate modified in step (1) with a zirconium source, a lithium source, and a dopant to obtain a mixture containing lithium zirconium borate; (3) pressing the mixture containing lithium zirconium borate in step (2) into tablets and transferring them into a primary sintering device, performing a high-temperature primary sintering under a slightly positive or negative pressure of dry air or an inert atmosphere, and then airflow crushing, screening, and demagnetization to obtain the doped and modified lithium zirconium borate; (4) dry-mixing and ball-milling the doped and modified lithium zirconium borate of step (3) with the coating agent, pressing the tablets into a secondary sintering device, and performing high-temperature secondary sintering under a slightly positive or negative pressure of dry air or an inert atmosphere, and then air flow crushing, screening, and demagnetization to obtain a modified oxide solid electrolyte material.

2. The method according to claim 1, characterized in that The mass ratio of BLiO2, Li2O, B4Li2O7 and LiF in step (1) is 0.6-1:0.6-1:0.5-1:0.0001-0.

02.

3. The method according to claim 1, characterized in that In step (1), the mixing ball milling speed is 100 to 1500 rpm, the mixing ball milling time is 0.5 to 8.0 hours, and the mixing ball to material ratio is 2 to 20:1; The pre-sintering constant temperature is 100-800°C, and the pre-sintering constant temperature time is 1.0-6.0h.

4. The method according to claim 1, characterized in that: The zirconium source in step (2) is selected from Zr(CO3)2, Zr(OH)4, ZrO2, Zr 0.92 O2Y 0.08 、Zr 0.97 O2Y 0.03 , Zr(CH3COO)4, ZrB2, ZrF4, ZrSiO4, Li2ZrO3, Zr(HPO4)2, ZrCl4, Zr(CH3COO)4·4H2O, Zr(C6H5O7)2, Zr(NO3)4, ZrS2; The lithium source is one or more selected from LiOH, LiOH·H2O, Li2CO3, LiNO3, Li3BO3, LiBO2, Li2O, LiI, LiCl or C2H3O2Li; The dopant is a combination of Cu3N, TiN and Al(H2PO4)3.

5. The method according to claim 4, characterized in that In step (2), the mass of the dopant accounts for 0.01% to 6% of the total mass of the lithium source, the fluorine-doped modified lithium borate and the zirconium source, wherein the mass ratio of the lithium source, the fluorine-doped modified lithium borate and the zirconium source is 1 to 10: 1 to 3: 1 to 3; The mass ratio of the total mass of the lithium source, fluorine-doped modified lithium borate and zirconium source to the Cu3N is 1.0:0.0001-0.02; The mass ratio of the total mass of the lithium source, fluorine-doped modified lithium borate and zirconium source to the TiN is 1.0:0.0001-0.02; The mass ratio of the total mass of the lithium source, fluorine-doped modified lithium borate and zirconium source to the Al(H2PO4)3 is 1.0:0.0001-0.

02.

6. The method according to claim 1, characterized in that In step (2), the mixing ball milling speed is 200 to 2500 rpm, the mixing ball milling time is 1.0 to 10.0 h, and the ball-to-material ratio of the mixing ball milling is 3 to 20:

1.

7. The method according to claim 1, characterized in that In step (3), the tableting pressure is 18 to 36 MPa, and the tableting time is 1 to 20 s; The primary sintering constant temperature is 200-2400°C, and the primary sintering constant temperature time is 2-32h.

8. The method according to claim 1, characterized in that: The coating agent in step (4) is a combination of AlN, TaN, LaN and C2H3O2Li; The mass ratio of the doped and modified lithium zirconium borate to the coating agent is 1:0.0001-0.040; The mass ratio of the doped and modified lithium zirconium borate to the C2H3O2Li is 1:0.0001-0.020, the mass ratio of the doped and modified lithium zirconium borate to the AlN is 1:0.0002-0.012, the mass ratio of the doped and modified lithium zirconium borate to the TaN is 1:0.0002-0.012, and the mass ratio of the doped and modified lithium zirconium borate to the LaN is 1:0.0002-0.012; In step (4), the tableting pressure is 10 to 20 MPa, and the tableting time is 1 to 10 s; The secondary sintering constant temperature is 100-1100° C., and the secondary sintering constant temperature time is 1-10 hours.

9. A modified oxide solid electrolyte material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the modified oxide solid electrolyte material according to claim 9 in the preparation of secondary batteries.

Images