Surface-modified oxide solid electrolyte powder, composite solid electrolyte, and preparation method therefor

Abstract

A surface-modified oxide solid electrolyte powder, a composite solid electrolyte, and a preparation method therefor. A surface of the surface-modified oxide solid electrolyte powder contains a first preset functional group. Oxide solid electrolytes include crystalline electrolytes and composites thereof, and amorphous electrolytes and composites thereof. The composition of the composite solid electrolyte comprises the surface-modified oxide solid electrolyte powder, a lithium salt, and a polymer containing an ether bond, and a surface of the composite solid electrolyte contains a second preset functional group. By modifying the surface of the oxide solid electrolyte powder, a chemical reaction is carried out between the oxide solid electrolyte powder and the polymer, so that the interfacial compatibility of the oxide solid electrolyte powder and the polymer is improved, the transfer uniformity of lithium ions in the composite solid electrolyte is improved, the ionic conductivity, mechanical properties, and thermal stability of the composite solid electrolyte are improved, the growth of lithium dendrites in the composite solid electrolyte is inhibited, and the safety performance is improved.

Description

Surface-modified oxide solid electrolyte powder, composite solid electrolyte and preparation method thereof

[0001] Cross-references

[0002] This application is based on the Chinese patent application with application number 202311170703.4 and application date September 12, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present invention relates to the technical field of lithium batteries, and in particular to a surface-modified oxide solid electrolyte powder, a composite solid electrolyte and a preparation method thereof. Background Art

[0004] As the most common energy storage method, lithium-ion batteries have been widely used in various fields such as portable electronic devices and grid energy storage. However, commercial lithium-ion batteries with organic liquid electrolytes have safety issues such as short circuit and thermal runaway, which may lead to explosion. In order to meet the commercial needs of future electric vehicles and energy storage, solid-state lithium batteries with high specific capacity and safety have attracted increasing attention. Solid-state electrolytes are key materials in all-solid-state batteries. In order to meet the needs of all-solid-state batteries, solid-state electrolytes should have several basic properties: high ionic conductivity exceeding 10-4S cm-1, excellent lithium dendrite suppression ability, strong mechanical flexibility, wide electrochemical window stability, stable chemical properties and low interface resistance to metallic lithium.

[0005] There are three main types of solid electrolytes: inorganic oxide solid electrolytes, polymer electrolytes and sulfide electrolytes. Sulfides have very high ionic conductivity, but are chemically unstable to metallic lithium and highly sensitive to air, making them difficult to use on a large scale. Inorganic oxide solid electrolytes have relatively high ionic conductivity (>10 -4 S cm -1 ) and good chemical stability; however, inorganic oxide solid electrolytes are brittle and have large interfacial resistance that hinders the transport of lithium ions through the interface. Polymer electrolytes are easy to process, making them compatible with current roll-to-roll technology, which has the lowest manufacturing cost. However, polymer electrolytes generally have low ionic conductivity and low mechanical strength at room temperature. Therefore, neither polymer electrolytes nor inorganic oxide solid electrolytes alone can meet the comprehensive requirements of all-solid-state batteries.

[0006] In order to overcome the limitations of polymer and inorganic oxide solid electrolytes, the composite electrolytes formed by adding inorganic oxide solid electrolytes to polymer electrolytes exhibit good comprehensive properties, namely, high ionic conductivity at room temperature, wide electrochemical window, and good contact with electrodes.

[0007] In composite solid electrolytes, due to the poor interfacial compatibility between polymer electrolytes and oxide solid electrolytes, oxide solid electrolytes tend to agglomerate in the polymer. At the same time, lithium ions lack an effective lithium-conducting network at the interface between the polymer electrolyte and the oxide solid electrolyte, which reduces the ionic conductivity of the composite solid electrolyte. In addition, the lack of interaction between the polymer electrolyte and the oxide solid electrolyte prevents close bonding, which is not conducive to the stability of the composite electrolyte system.

[0008] Summary of the Invention

[0009] The purpose of the embodiments of the present invention is to provide a surface-modified oxide solid electrolyte powder, a composite solid electrolyte and a preparation method thereof. By modifying the surface of the oxide solid electrolyte powder, a chemical reaction occurs between the oxide solid electrolyte powder and the polymer, thereby improving the interfacial compatibility between the oxide solid electrolyte powder and the polymer, improving the uniformity of lithium ion transfer in the composite solid electrolyte, improving the ionic conductivity, mechanical properties and thermal stability of the composite solid electrolyte, and inhibiting the growth of lithium dendrites inside the composite solid electrolyte, thereby improving safety performance.

[0010] To solve the above technical problems, a first aspect of an embodiment of the present invention provides a surface-modified oxide solid electrolyte powder, wherein the surface of the surface-modified oxide solid electrolyte powder contains a first preset functional group;

[0011] The oxide solid electrolyte includes one or both of a crystalline electrolyte and a composite thereof and an amorphous electrolyte and a composite thereof.

[0012] Furthermore, the first preset functional group includes at least one of a phenolic hydroxyl group, an amino group, an imino group, a carbon-nitrogen double bond, a carbon-nitrogen single bond, a methylene group, an ester group, a thiazolyl group, and a carbonyl group;

[0013] Preferably, the first preset functional group includes at least one of a phenolic hydroxyl group, an amino group, an imino group and a carbon-nitrogen single bond.

[0014] Further, the additives for surface modification include: at least one of dopamine, 3,5-dichlorophenol, bis(2,4,6-trichlorophenyl)oxalate, 2,3-dimethylphenol, p-hydroxyphenylethanol, venlafaxine hydrochloride, propofol, 2-hydroxy-1-naphthaldehyde, propyl gallate, 3,4-dichlorophenol, polyethyleneimine, 1,3-benzothiazol-5-amine, 2,4-dichloroaniline, 3-bromo-1,2-diaminobenzene, (1-(4-amino-2-fluorophenyl)piperidin-4-yl)carbamic acid tert-butyl ester, 2-chloro-5-methylaniline, 2,5-dichloroaniline, 2-amino-5-chlorobenzophenone, o-bromoaniline, 4-bromo-2,6-difluoroaniline and 4-amino-2-methoxyphenol;

[0015] Preferably, the additive for surface modification includes at least one of polydopamine, p-hydroxyphenylethanol, polyethyleneimine and 2,5-dichloroaniline.

[0016] Furthermore, the mass fraction W1 of the additive for surface modification in the oxide solid electrolyte powder is: 0.5wt%≤W1≤15wt%, preferably 1wt%≤W1≤10wt%.

[0017] Furthermore, the crystalline electrolyte includes: sodium superion conductor structure electrolyte, lithium superion conductor structure electrolyte, perovskite structure electrolyte and garnet structure electrolyte crystalline electrolyte, and the amorphous electrolyte includes: lithium phosphorus oxygen nitrogen;

[0018] Preferably, the crystalline electrolyte includes: a garnet structure electrolyte.

[0019] Furthermore, the garnet structure electrolyte is lithium zirconate (LLZO), whose molecular formula is Li 7-x La 3-y Zr 2-z M α O 12-β D δ ;

[0020] Optionally, the doping element M includes at least one of Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W, and rare earth elements other than La; the doping element D includes at least one of N, F, P, and S, and 0≤x≤3, 0≤y≤1.5, 0≤z≤1, 0<α<3, 0≤β≤1.5, and 0≤δ≤1;

[0021] Preferably, the doping element M includes at least one of Mn, Fe, Co, Ni, Al, Ga, Nb, Ta, Ce, Pr, Nd, Sm, Gd, Yb and Y, and the doping element D includes at least one of F and S.

[0022] Accordingly, a second aspect of an embodiment of the present invention provides a method for preparing a surface-modified oxide solid electrolyte powder, which is used to prepare any of the surface-modified oxide solid electrolyte powders described above, comprising the following steps:

[0023] adding oxide solid electrolyte powder and an additive for surface modification into a first organic solvent to obtain an oxide solid electrolyte powder dispersion and an additive solution, respectively;

[0024] The oxide solid electrolyte powder dispersion and the additive solution are fully mixed at a first preset temperature according to a first preset ratio, and then filtered, washed, and dried to obtain a surface-modified oxide solid electrolyte powder.

[0025] Furthermore, the first preset temperature is 20°C-70°C, preferably 30°C-50°C;

[0026] The mixing time is 0.5h-12h, preferably 3h-8h.

[0027] Furthermore, the temperature of the drying process is 30°C-80°C, preferably 40°C-60°C;

[0028] The drying process takes 6 hours to 48 hours, preferably 12 hours to 24 hours.

[0029] Furthermore, the mass fraction W1 of the surface modification additive in the first preset ratio to the oxide solid electrolyte powder is: 0.5wt%≤W1≤15wt%, preferably 1wt%≤W1≤10wt%.

[0030] Furthermore, the first organic solvent includes at least one of 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 and water and a mixture thereof.

[0031] Accordingly, a third aspect of an embodiment of the present invention provides a composite solid electrolyte, which comprises any of the surface-modified oxide solid electrolyte powders described above, a polymer containing ether bonds, and a lithium salt, wherein the surface of the composite solid electrolyte contains a second preset functional group.

[0032] Furthermore, the second preset functional group includes: one or more of phenolic hydroxyl group, amino group, imino group, carbon-nitrogen double bond, carbon-nitrogen single bond, methylene group, amino ether bond, ester group, thiazolyl group, and carbonyl group; preferably, the second preset functional group includes: one or more of phenolic hydroxyl group, amino group, imino group, carbon-nitrogen double bond, carbon-nitrogen single bond, methylene group, and amino ether bond.

[0033] Furthermore, the polymer containing ether bonds includes at least one of polyethylene oxide, polypropylene oxide, butylene oxide, polytetramethylene oxide, polymethyl ether, polyethyl ether, polypropyl ether, polybutyl ether, polyetheretherketone, polyetherketone, polyetherketoneketone and polyetheramine;

[0034] Preferably, the polymer containing ether bonds includes at least one of polyethylene oxide, polypropylene oxide, butylene oxide and polymethyl ether.

[0035] Furthermore, the lithium salt includes at least one of lithium hexafluorophosphate, lithium perfluoroalkyl phosphate, lithium tetrafluorooxalatophosphate, lithium perchlorate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl imide) and lithium bis(fluorosulfonyl imide);

[0036] Preferably, the lithium salt includes at least one of lithium bis(trifluoromethylsulfonyl)imide, lithium perchlorate and lithium difluorooxalatoborate.

[0037] Furthermore, the mass fraction W2 of the surface-modified oxide solid electrolyte powder in the composite solid electrolyte is: 20wt%≤W2≤90wt%, preferably 30wt%≤W2≤80wt%;

[0038] The mass fraction W3 of the polymer containing ether bonds in the composite solid electrolyte is: 5wt%≤W3≤65wt%, preferably 10wt%≤W3≤50wt%;

[0039] The mass fraction W4 of the lithium salt in the composite solid electrolyte is: 5wt%≤W4≤20wt%, preferably 7wt%≤W4≤18wt%.

[0040] Accordingly, a fourth aspect of an embodiment of the present invention provides a method for preparing a composite solid electrolyte, which is used to prepare any of the composite solid electrolytes described above, comprising the following steps:

[0041] dissolving a polymer containing an ether bond and a lithium salt in a second organic solvent to obtain a polymer slurry containing an ether bond, dispersing a surface-modified oxide solid electrolyte powder in the second organic solvent to obtain an oxide electrolyte slurry, and thoroughly mixing the oxide electrolyte slurry with the polymer slurry containing an ether bond in a second preset ratio to obtain a composite solid electrolyte slurry containing a surface-modified oxide solid electrolyte;

[0042] The composite solid electrolyte slurry is coated on a support membrane once or multiple times, and dried at a second preset temperature for a second preset time to obtain one or more layers of a composite solid electrolyte membrane or composite solid electrolyte tape / sheet containing a surface-modified oxide electrolyte of a first preset thickness.

[0043] Furthermore, the second organic solvent includes: at least one of 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 and water.

[0044] Furthermore, the second preset temperature is 40°C-90°C, preferably 50°C-80°C;

[0045] The second preset duration is 5 hours to 48 hours, preferably 8 hours to 24 hours.

[0046] Furthermore, the first preset thickness of the composite solid electrolyte is 10 μm-100 μm; preferably, the thickness of the composite solid electrolyte is 20 μm-60 μm.

[0047] Furthermore, in the second preset ratio, the mass fraction W2 of the surface-modified oxide solid electrolyte powder in the composite solid electrolyte is: 20wt% ≤ W2 ≤ 90wt%, preferably 30wt% ≤ W2 ≤ 80wt%; the mass fraction W3 of the polymer containing ether bonds in the composite solid electrolyte is: 5wt% ≤ W3 ≤ 65wt%, preferably 10wt% ≤ W3 ≤ 50wt%; the mass fraction W4 of the lithium salt in the composite solid electrolyte is: 5wt% ≤ W4 ≤ 20wt%, preferably 7wt% ≤ W4 ≤ 18wt%.

[0048] Correspondingly, the fifth aspect of the embodiments of the present invention further provides an application of a composite solid electrolyte in an all-solid-state lithium metal or lithium ion battery, a semi-solid lithium ion battery, and a lithium-air battery.

[0049] The above technical solutions of the embodiments of the present invention have the following beneficial technical effects:

[0050] By modifying the surface of the oxide solid electrolyte powder, a chemical reaction occurs between the oxide solid electrolyte powder and the polymer, thereby improving the interfacial compatibility between the oxide solid electrolyte powder and the polymer, enhancing the uniformity of lithium ion transfer in the composite solid electrolyte, and improving the ionic conductivity, mechanical properties, and thermal stability of the composite solid electrolyte. Furthermore, the growth of lithium dendrites within the composite solid electrolyte is inhibited, thereby improving safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG1 is a flow chart of a method for preparing a composite solid electrolyte according to an embodiment of the present invention;

[0052] FIG2 is a schematic diagram of a process for preparing a composite solid electrolyte according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. 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 unnecessary confusion of the concepts of the present invention.

[0054] A first aspect of an embodiment of the present invention provides a surface-modified oxide solid electrolyte powder, wherein the surface of the surface-modified oxide solid electrolyte powder contains a first preset functional group; the oxide solid electrolyte includes: one or both of a crystalline electrolyte and its composite and an amorphous electrolyte and its composite.

[0055] Furthermore, the first preset functional group includes: at least one of a phenolic hydroxyl group, an amino group, an imino group, a carbon-nitrogen double bond, a carbon-nitrogen single bond, a methylene group, an ester group, a thiazolyl group and a carbonyl group; preferably, the first preset functional group includes: at least one of a phenolic hydroxyl group, an amino group, an imino group and a carbon-nitrogen single bond, and preferably the first preset functional group can produce a chemical bond with a polymer containing an ether bond to construct a more efficient lithium ion transport network, so that the composite solid electrolyte has higher ionic conductivity.

[0056] Further, the additives for surface modification include: at least one of dopamine, 3,5-dichlorophenol, bis(2,4,6-trichlorophenyl)oxalate, 2,3-dimethylphenol, p-hydroxyphenylethanol, venlafaxine hydrochloride, propofol, 2-hydroxy-1-naphthaldehyde, propyl gallate, 3,4-dichlorophenol, polyethyleneimine, 1,3-benzothiazol-5-amine, 2,4-dichloroaniline, 3-bromo-1,2-diaminobenzene, (1-(4-amino-2-fluorophenyl)piperidin-4-yl)carbamic acid tert-butyl ester, 2-chloro-5-methylaniline, 2,5-dichloroaniline, 2-amino-5-chlorobenzophenone, o-bromoaniline, 4-bromo-2,6-difluoroaniline and 4-amino-2-methoxyphenol;

[0057] Preferably, the additive for surface modification includes at least one of polydopamine, p-hydroxyphenylethanol, polyethyleneimine, and 2,5-dichloroaniline, and at least one of the additive for surface modification and the first predetermined functional group provided by the additive is present on the surface of the oxide solid electrolyte powder.

[0058] Furthermore, the mass fraction W1 of the additive used for surface modification in the oxide solid electrolyte powder is: 0.5wt%≤W1≤15wt%, preferably 1wt%≤W1≤10wt%.

[0059] Furthermore, the crystalline electrolyte includes: sodium superion conductor structure electrolyte, lithium superion conductor structure electrolyte, perovskite structure electrolyte and garnet structure electrolyte crystalline electrolyte, and the amorphous electrolyte includes: lithium phosphorus oxygen nitrogen; preferably, the crystalline electrolyte includes: garnet structure electrolyte.

[0060] Furthermore, the garnet structure electrolyte is lithium zirconate (LLZO), whose molecular formula is Li 7-x La 3-y Zr 2-z M α O 12-β D δ ; Optionally, the doping element M includes: Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W and at least one of the rare earth elements other than La, and the doping element D includes: at least one of N, F, P and S, and 0≤x≤3, 0≤y≤1.5, 0≤z≤1, 0<α<3, 0≤β≤1.5, 0≤δ≤1; Preferably, the doping element M includes: at least one of Mn, Fe, Co, Ni, Al, Ga, Nb, Ta, Ce, Pr, Nd, Sm, Gd, Yb and Y, and the doping element D includes: at least one of F and S.

[0061] Accordingly, a second aspect of an embodiment of the present invention provides a method for preparing a surface-modified oxide solid electrolyte powder, which is used to prepare any of the above-mentioned surface-modified oxide solid electrolyte powders, comprising the following steps:

[0062] Step S110 , adding oxide solid electrolyte powder and an additive for surface modification into a first organic solvent, respectively, to obtain an oxide solid electrolyte powder dispersion and an additive solution, respectively.

[0063] Step S120 , fully mixing the oxide solid electrolyte powder dispersion and the additive solution at a first preset temperature according to a first preset ratio, and filtering, washing, and drying to obtain surface-modified oxide solid electrolyte powder.

[0064] Specifically, the first preset temperature is 20°C-70°C, preferably 30°C-50°C; the mixing time is 0.5h-12h, preferably 3h-8h. Within the preferred first preset temperature range and mixing time range, the surface modification additive of the obtained oxide solid electrolyte powder is evenly distributed.

[0065] Specifically, the temperature of the drying process is 30°C-80°C, preferably 40°C-60°C; the time of the drying process is 6h-48h, preferably 12h-24h. Within the preferred drying process temperature and drying process time range, the surface-modified oxide solid electrolyte powder has the best weight loss effect during the drying process.

[0066] Furthermore, the mass fraction W1 of the surface modification additive in the first preset ratio to the oxide solid electrolyte powder is: 0.5wt%≤W1≤15wt%, preferably 1wt%≤W1≤10wt%. Within the preferred mass fraction W1 range, the oxide solid electrolyte powder and the polymer have better interfacial compatibility.

[0067] Optionally, the first organic solvent includes at least one of 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 and water and a mixture thereof.

[0068] Accordingly, a third aspect of an embodiment of the present invention provides a composite solid electrolyte, which comprises any of the above-mentioned surface-modified oxide solid electrolyte powders, a lithium salt containing an ether bond polymer and a composition, the surface of the composite solid electrolyte contains a second preset functional group, and the composite solid electrolyte includes a composite solid electrolyte membrane.

[0069] The above technical solution modifies the surface of the oxide solid electrolyte powder, causing the oxide solid electrolyte powder and the polymer to react chemically, thereby improving the interfacial compatibility between the oxide solid electrolyte powder and the polymer, creating a chemical bond between the oxide solid electrolyte powder and the polymer, improving the uniformity of lithium ion transfer in the composite solid electrolyte, enhancing the mechanical properties and thermal stability of the solid electrolyte, and inhibiting the growth of lithium dendrites within the composite solid electrolyte. Composite solid electrolytes containing surface-modified oxide solid electrolytes exhibit high ionic conductivity, good mechanical properties, excellent thermal stability and safety performance, and the ability to inhibit lithium dendrites. They can be used in all-solid-state lithium metal or lithium-ion batteries, semi-solid lithium-ion batteries, lithium-air batteries and other fields.

[0070] Optionally, the second preset functional group includes one or more of: phenolic hydroxyl, amino, imino, carbon-nitrogen double bond, carbon-nitrogen single bond, methylene, amino ether bond, ester group, thiazolyl, and carbonyl. Preferably, the second preset functional group includes one or more of: phenolic hydroxyl, amino, imino, carbon-nitrogen double bond, carbon-nitrogen single bond, methylene, and amino ether bond. Preferably, the second preset functional group can promote the dissociation of lithium salts, so that the polymer contains more free Li + , which improves the mobility and uniformity of lithium ions, and the composite solid electrolyte has better stability to lithium

[0071] Optionally, the polymer containing ether bonds includes: at least one of polyethylene oxide, polypropylene oxide, butylene oxide, polytetramethylene oxide, polymethyl ether, polyethyl ether, polypropyl ether, polybutyl ether, polyether ether ketone, polyether ketone, polyether ketone ketone and polyether amine; preferably, the polymer containing ether bonds includes: at least one of polyethylene oxide, polypropylene oxide, butylene oxide and polymethyl ether.

[0072] Optionally, the lithium salt includes at least one of lithium hexafluorophosphate, lithium perfluoroalkyl phosphate, lithium tetrafluorooxalatophosphate, lithium perchlorate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethylsulfonylimide) and lithium bis(fluorosulfonylimide); preferably, the lithium salt includes at least one of lithium bis(trifluoromethylsulfonylimide), lithium perchlorate and lithium difluorooxalatoborate.

[0073] Specifically, the mass fraction W2 of the surface-modified oxide solid electrolyte powder in the composite solid electrolyte is: 20wt% ≤ W2 ≤ 90wt%, preferably 30wt% ≤ W2 ≤ 80wt%; the mass fraction W3 of the polymer containing ether bonds in the composite solid electrolyte is: 5wt% ≤ W3 ≤ 65wt%, preferably 10wt% ≤ W3 ≤ 50wt%; the mass fraction W4 of the lithium salt in the composite solid electrolyte is: 5wt% ≤ W4 ≤ 20wt%, preferably 7wt% ≤ W4 ≤ 18wt%.

[0074] Accordingly, a fourth aspect of an embodiment of the present invention provides a method for preparing a composite solid electrolyte, which is used to prepare any of the above composite solid electrolytes, comprising the following steps:

[0075] In step S210, a polymer containing an ether bond and a lithium salt are dissolved in a second organic solvent to obtain a polymer slurry containing an ether bond, the surface-modified oxide solid electrolyte powder is dispersed in a second organic solvent to obtain an oxide electrolyte slurry, and the oxide electrolyte slurry and the polymer slurry containing an ether bond are fully mixed according to a second preset ratio to obtain a composite solid electrolyte slurry containing a surface-modified oxide solid electrolyte.

[0076] In step S220, the composite solid electrolyte slurry is coated on the support membrane once or multiple times, and dried at a second preset temperature for a second preset time to obtain one or more layers of a composite solid electrolyte membrane or composite solid electrolyte tape / sheet containing a surface-modified oxide electrolyte of a first preset thickness. The multi-layer composite solid electrolyte membrane or composite solid electrolyte tape / sheet exhibits better lithium stability and mechanical properties.

[0077] Furthermore, the second organic solvent includes: at least one of 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 and water.

[0078] Furthermore, the second preset temperature is 40°C-90°C, preferably 50°C-80°C;

[0079] The second preset duration is 5h-48h, preferably 8h-24h.

[0080] Furthermore, the first preset thickness of the composite solid electrolyte is 10 μm-100 μm; preferably, the thickness of the composite solid electrolyte is 20 μm-60 μm.

[0081] Furthermore, in the second preset ratio, the mass fraction W2 of the surface-modified oxide solid electrolyte powder in the composite solid electrolyte is: 20wt% ≤ W2 ≤ 90wt%, preferably 30wt% ≤ W2 ≤ 80wt%; the mass fraction W3 of the polymer containing ether bonds in the composite solid electrolyte is: 5wt% ≤ W3 ≤ 65wt%, preferably 10wt% ≤ W3 ≤ 50wt%; the mass fraction W4 of the lithium salt in the composite solid electrolyte is: 5wt% ≤ W4 ≤ 20wt%, preferably 7wt% ≤ W4 ≤ 18wt%.

[0082] The above-mentioned preparation method generates a chemical bond between the oxide solid electrolyte powder and the polymer containing an ether bond through surface modification, thereby improving the interfacial compatibility between the oxide solid electrolyte powder and the polymer containing an ether bond, enhancing the uniformity of lithium ion transfer, improving the mechanical properties and thermal stability of the solid electrolyte membrane or belt, and inhibiting the growth of lithium dendrites inside the composite solid electrolyte. The composite solid electrolyte containing the surface-modified oxide solid electrolyte exhibits high ionic conductivity, good mechanical properties, excellent thermal stability and safety performance, and the ability to inhibit lithium dendrites. It can be used in the fields of all-solid-state lithium metal or lithium ion batteries, semi-solid lithium ion batteries, lithium-air batteries, etc. The method used has the advantages of simple process, low cost and strong universality, and is suitable for large-scale application.

[0083] Correspondingly, the fifth aspect of the embodiments of the present invention further provides an application of a composite solid electrolyte in an all-solid-state lithium metal or lithium ion battery, a semi-solid lithium ion battery, and a lithium-air battery.

[0084] The preparation method of the composite solid electrolyte is further described below with reference to a comparative example and several examples.

[0085] Comparative Example 1

[0086] Li7La3Zr 1.75 Nb 0.25 O 12 Dispersed in acetonitrile to obtain Li7La3Zr 1.75 Nb 0.25 O 12 In an argon-filled environment, polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:1 to obtain a polymer slurry. Li7La3Zr 1.75 Nb 0.25 O 12 The polymer slurry was dispersed in acetonitrile to obtain an oxide electrolyte slurry, and the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface-modified Li7La3Zr 1.75 Nb 0.25 O12 The composite solid electrolyte slurry was coated on the support membrane and dried in a vacuum drying oven at 40 ° C for 5 h to obtain a composite solid electrolyte slurry containing Li7La3Zr 1.75 Nb 0.25 O 12 The composite solid electrolyte has a thickness of 100 microns.

[0087] Example 1

[0088] Li7La3Zr 1.75 Nb 0.25 O 12 , dopamine and polyethyleneimine were dispersed and dissolved in methanol at a mass ratio of 1:0.005 to obtain Li7La3Zr 1.75 Nb 0.25 O 12 The dispersion and the mixed solution of dopamine and polyethyleneimine were fully mixed at 20 ° C for 0.5 h, filtered, washed, and dried at 30 ° C for 6 h to obtain Li7La3Zr 1.75 Nb 0.25 O 12 In an argon-filled environment, polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:1 to obtain a polymer slurry. Li7La3Zr with a surface containing phenolic hydroxyl groups, amino groups, and imino groups at a mass ratio of 1:0.06 to polyethylene oxide was dissolved in acetonitrile. 1.75 Nb 0.25 O 12 The polymer slurry was dispersed in acetonitrile to obtain an oxide electrolyte slurry, and the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface-modified Li7La3Zr 1.75 Nb 0.25 O 12 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 40°C for 5 hours to obtain a composite solid electrolyte containing phenolic hydroxyl groups, amino groups, and imino groups. The thickness of the composite electrolyte was 100 μm.

[0089] Example 2

[0090] Li 6.25 La3Zr2Al 0.25 O 12 , 3,5-dichlorophenol and 1,3-benzothiazol-5-amine were dispersed and dissolved in methanol at a mass ratio of 1:0.15 to obtain Li 6.25 La3Zr2Al 0.25 O 12The dispersion and the mixed solution of 3,5-dichlorophenol and 1,3-benzothiazol-5-amine were fully mixed at 70 ° C for 12 h, filtered, washed, and dried at 80 ° C for 48 h to obtain Li 6.25 La3Zr2Al 0.25 O 12 In an argon-filled environment, polyacrylonitrile and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:4 to obtain a polymer slurry. Lithium bis(trifluoromethanesulfonyl)imide with carbon-nitrogen double bonds, carbon-nitrogen single bonds, and methylene groups on the surface of the polymer was dissolved in acetonitrile at a mass ratio of 1:0.07 to polyacrylonitrile. 6.25 La3Zr2Al 0.25 O 12 Dispersed in acetonitrile to obtain oxide electrolyte slurry, the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface modified Li 6.25 La3Zr2Al 0.25 O 12 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 90°C for 48 hours to obtain a composite solid electrolyte containing carbon-nitrogen double bonds, carbon-nitrogen single bonds, and methylene groups on the surface. The thickness of the composite electrolyte was 10 microns.

[0091] Example 3

[0092] Li7La3Zr2O 12 , bis(2,4,6-trichlorophenyl)oxalate, and 2,4-dichloroaniline were dispersed and dissolved in methanol at a mass ratio of 1:0.01 to obtain Li7La3Zr2O 12 The dispersion and the mixed solution of bis(2,4,6-trichlorophenyl) oxalate and 2,4-dichloroaniline were fully mixed at 30 ° C for 3 h, filtered, washed, and dried at 40 ° C for 12 h to obtain Li7La3Zr2O with ester groups, thiazole groups, and carbonyl groups on the surface. 12 In an argon-filled environment, polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:0.04 to obtain a polymer slurry. Li7La3Zr2O3 containing ester groups, thiazole groups, and carbonyl groups on the surface was dissolved in a mass ratio of 1:3.75 to polyvinylidene fluoride. 12 The polymer slurry was dispersed in acetonitrile to obtain an oxide electrolyte slurry, and the polymer slurry was fully mixed with the oxide electrolyte slurry to obtain a surface-modified Li7La3Zr2O 12 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 50°C for 8 hours to obtain a composite solid electrolyte with amino ether bonds, ester groups, and thiazole groups on the surface. The thickness of the composite electrolyte was 20 microns.

[0093] Example 4

[0094] Li 6.4 La3Zr 1.4 Ta 0.6 O 12 , 2,3-dimethylphenol and 3-bromo-1,2-diaminobenzene were dispersed and dissolved in methanol at a mass ratio of 1:0.1 to obtain Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The dispersion and the mixed solution of 2,3-dimethylphenol and 3-bromo-1,2-diaminobenzene were fully mixed at 50 ° C for 8 h, filtered, washed, and dried at 60 ° C for 24 h to obtain Li 6.4 La3Zr 1.4 Ta 0.6 O 12 In an argon-filled environment, polyvinylidene fluoride and lithium perchlorate were completely dissolved in acetonitrile at a mass ratio of 1:0.31 to obtain a polymer slurry. Lithium perchlorate with a mass ratio of 1:4.33 to polyvinylidene fluoride containing phenolic hydroxyl groups, amino groups, and imino groups on the surface was dissolved in acetonitrile. 6.4 La3Zr 1.4 Ta 0.6 O 12 Dispersed in acetonitrile to obtain oxide electrolyte slurry, the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface modified Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 80°C for 24 hours to obtain a composite solid electrolyte containing phenolic hydroxyl groups, amino groups, and imino groups on the surface. The thickness of the composite electrolyte was 60 microns.

[0095] Example 5

[0096] Li 6.4 La3Zr 1.4 Nb 0.6 O 12 , p-hydroxyphenylethanol and (1-(4-amino-2-fluorophenyl)piperidin-4-yl)carbamic acid tert-butyl ester were dispersed and dissolved in methanol at a mass ratio of 1:0.03 to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12The dispersion and the mixed solution of p-hydroxyphenylethanol, hydroxyphenylethanol and (1-(4-amino-2-fluorophenyl)piperidin-4-yl)carbamic acid tert-butyl ester were fully mixed at 40 ° C for 6 h, filtered, washed, and dried at 50 ° C for 18 h to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 In an argon-filled environment, polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:6 to obtain a polymer slurry. Lithium bis(trifluoromethanesulfonyl)imide) with amino groups, imino groups and carbon-nitrogen single bonds on its surface was dissolved in a mass ratio of 1:0.33 to polyethylene oxide. 6.4 La3Zr 1.4 Nb 0.6 O 12 Dispersed in acetonitrile to obtain oxide electrolyte slurry, the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface modified Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 60°C for 18 hours to obtain a composite solid electrolyte containing phenolic hydroxyl groups, amino groups, and carbon-nitrogen double bonds on the surface. The thickness of the composite electrolyte was 30 microns.

[0097] Example 6

[0098] Li 6.5 La3Zr2O 11.9 F 0.2 , venlafaxine hydrochloride and 2-chloro-5-methylaniline were dispersed and dissolved in methanol at a mass ratio of 1:0.07 to obtain Li 6.5 La3Zr2O 11.9 F 0.2 The dispersion and the mixed solution of venlafaxine hydrochloride and 2-chloro-5-methylaniline were fully mixed at 45 ° C for 8 h, filtered, washed, and dried at 60 ° C for 18 h to obtain Li 6.5 La3Zr2O 11.9 F 0.2 In an argon-filled environment, polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:0.54 to obtain a polymer slurry. Lithium bis(trifluoromethanesulfonyl)imide) with a surface containing phenolic hydroxyl groups, imino groups, and carbon-nitrogen double bonds was dissolved in a mass ratio of 1:0.16 to polyethylene oxide. 6.5 La3Zr2O 11.9 F 0.2Dispersed in acetonitrile to obtain oxide electrolyte slurry, the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface modified Li 6.5 La3Zr2O 11.9 F 0.2 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 60°C for 18 hours to obtain a composite solid electrolyte containing phenolic hydroxyl groups, amino groups, and carbon-nitrogen single bonds on the surface. The thickness of the composite electrolyte was 50 microns.

[0099] Example 7

[0100] Li 6.4 La3Zr 1.4 Nb 0.6 O 12 , propofol and 2,5-dichloroaniline were dispersed and dissolved in methanol at a mass ratio of 1:0.04 to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The dispersion and the mixed solution of propofol and 2,5-dichloroaniline were fully mixed at 50 ° C for 8 h, filtered, washed, and dried at 60 ° C for 18 h to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 In an argon-filled environment, polyvinylidene fluoride and lithium perchlorate were completely dissolved in acetonitrile at a mass ratio of 1:0.36 to obtain a polymer slurry. Lithium perchlorate with a mass ratio of 1:1.56 to polyvinylidene fluoride containing phenolic hydroxyl groups, amino groups, and carbon-nitrogen single bonds on the surface was dissolved in acetonitrile. 6.4 La3Zr 1.4 Nb 0.6 O 12 Dispersed in acetonitrile to obtain oxide electrolyte slurry, the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface modified Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The composite solid electrolyte slurry was coated on a support membrane and dried in a vacuum drying oven at 60°C for 18 hours to obtain a composite solid electrolyte containing phenolic hydroxyl groups, amino groups, and methylene groups on the surface. The thickness of the composite electrolyte was 35 microns.

[0101] Example 8

[0102] In an argon-filled environment, polyvinylidene fluoride and lithium perchlorate were completely dissolved in acetonitrile at a mass ratio of 1:0.36 to obtain a polymer slurry. 6.4 La3Zr1.4 Nb 0.6 O 12 , dopamine and polyethyleneimine were dispersed and dissolved in methanol at a mass ratio of 1:0.04 to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The dispersion and the mixed solution of dopamine and polyethyleneimine were fully mixed at 50 ° C for 8 h, filtered, washed, and dried at 60 ° C for 18 h to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The surface of Li-ion batteries containing phenolic hydroxyl, amino and imino groups was prepared at a mass ratio of 1:1.56 to polyvinylidene fluoride. 6.4 La3Zr 1.4 Nb 0.6 O 12 The polymer slurry was dispersed in acetonitrile to obtain oxide electrolyte slurry 1, and the polymer slurry was fully mixed with the oxide electrolyte slurry 1 to obtain a surface modified Li 6.4 La3Zr 1.4 Nb 0.6 O 12 Composite solid electrolyte slurry 1. Li 6.4 La3Zr 1.4 Nb 0.6 O 12 , 3,5-dichlorophenol and 1,3-benzothiazol-5-amine were dispersed and dissolved in methanol at a mass ratio of 1:0.04 to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The dispersion and the mixed solution of 3,5-dichlorophenol and 1,3-benzothiazol-5-amine were fully mixed at 50 ° C for 8 h, filtered, washed, and dried at 60 ° C for 18 h to obtain Li 6.4 La3Zr 1.4 Nb 0.6 O 12 The surface of Li-ion battery containing carbon-nitrogen double bonds, carbon-nitrogen single bonds, and methylene groups was prepared at a mass ratio of 1:1.56 to polyvinylidene fluoride. 6.4 La3Zr 1.4 Nb 0.6 O 12 The polymer slurry was dispersed in acetonitrile to obtain oxide electrolyte slurry 2, and the polymer slurry was fully mixed with the oxide electrolyte slurry 2 to obtain a surface modified Li 6.4 La3Zr 1.4 Nb 0.6 O12 Composite solid electrolyte slurry 2. Composite solid electrolyte slurry 1 is coated on the support membrane and dried in a vacuum drying oven at 60°C for 8 hours. Composite solid electrolyte slurry 2 is then coated on the above composite solid electrolyte and dried in a vacuum drying oven at 60°C for 8 hours. Composite solid electrolyte slurry 1 is then coated on the above composite solid electrolyte and dried in a vacuum drying oven at 60°C for 8 hours to obtain a three-layer composite solid electrolyte containing phenolic hydroxyl groups, amino groups, and imino groups on the surface. The thickness of the composite electrolyte is 40 microns.

[0103] Example 9

[0104] In an argon-filled environment, polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were completely dissolved in acetonitrile at a mass ratio of 1:1 to obtain a polymer slurry. 12 , bis(2,4,6-trichlorophenyl) oxalate, and 2,4-dichloroaniline were dispersed and dissolved in methanol at a mass ratio of 1:0.04 to obtain Li7La3Zr2O 12 The dispersion and the mixed solution of bis(2,4,6-trichlorophenyl) oxalate and 2,4-dichloroaniline were fully mixed at 30 ° C for 3 h, filtered, washed, and dried at 40 ° C for 12 h to obtain Li7La3Zr2O with ester groups, thiazole groups, and carbonyl groups on the surface. 12 The surface of Li7La3Zr2O containing ester group, thiazole group and carbonyl group was prepared with a mass ratio of 1:3.75 to polyvinylidene fluoride. 12 The polymer slurry was dispersed in acetonitrile to obtain an oxide electrolyte slurry 1, and the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface-modified Li7La3Zr2O 12 Composite solid electrolyte slurry 1. Li7La3Zr2O 12 , 2,3-dimethylphenol and 3-bromo-1,2-diaminobenzene were dispersed and dissolved in methanol at a mass ratio of 1:0.04 to obtain Li7La3Zr2O 12 The dispersion and the mixed solution of 2,3-dimethylphenol and 3-bromo-1,2-diaminobenzene were fully mixed at 30 ° C for 3 h, filtered, washed, and dried at 40 ° C for 12 h to obtain Li7La3Zr2O containing phenolic hydroxyl, amino and imino groups on the surface. 12 The surface of Li7La3Zr2O containing phenolic hydroxyl, amino and imino groups was prepared at a mass ratio of 1:3.75 to polyvinylidene fluoride. 12 The polymer slurry was dispersed in acetonitrile to obtain oxide electrolyte slurry 2, and the polymer slurry and the oxide electrolyte slurry were fully mixed to obtain a surface-modified Li7La3Zr2O 12Composite solid electrolyte slurry 2. Composite solid electrolyte slurry 1 was applied to the support membrane and dried in a vacuum drying oven at 60°C for 8 hours. Composite solid electrolyte slurry 2 was then applied to the composite solid electrolyte and dried in a vacuum drying oven at 60°C for 8 hours. Composite solid electrolyte slurries 1 and 2 were applied sequentially using the same method and dried in a vacuum drying oven at 60°C for 8 hours to obtain a four-layer composite solid electrolyte with amino ether bonds, ester groups, and thiazole groups on the surface. The thickness of the composite electrolyte was 45 microns.

[0105] Examples 10-35

[0106] The same method as in Example 7 was followed, except that the polymer slurry containing ether bonds and the oxide electrolyte slurry were prepared in the desired stoichiometric ratio, and the additives for surface modification of the oxide solid electrolyte powder were also prepared in the desired stoichiometric ratio. Specific parameters and properties of the example are shown in Table 1.

[0107] Examples 36-38

[0108] The same method as Example 9 was followed, except that the polymer slurry containing ether bonds and the oxide electrolyte slurry were prepared in the required stoichiometric ratio, and the additives for surface modification of the oxide solid electrolyte powder were also prepared in the required stoichiometric ratio. Specific parameters and properties of the example are shown in Table 1.

[0109] Table 1

[0110] The embodiments of the present invention are intended to protect a surface-modified oxide solid electrolyte powder, a composite solid electrolyte, and a preparation method thereof. The surface-modified oxide solid electrolyte powder comprises a first predetermined functional group on its surface; the oxide solid electrolyte comprises: a crystalline electrolyte and a composite thereof, and an amorphous electrolyte and a composite thereof. The above technical solution has the following effects:

[0111] By modifying the surface of oxide solid electrolyte powders, a chemical reaction occurs between the oxide solid electrolyte powders and the polymer electrolyte, thereby improving the interfacial compatibility between the oxide solid electrolyte powders and the polymer, enhancing the uniformity of lithium ion transfer, improving the mechanical properties and thermal stability of the solid electrolyte, and inhibiting the growth of lithium dendrites within the composite solid electrolyte. Composite solid electrolytes containing surface-modified oxide solid electrolytes exhibit high ionic conductivity, good mechanical properties, excellent thermal stability and safety, and the ability to inhibit lithium dendrites. They can be used in all-solid-state lithium metal or lithium-ion batteries, semi-solid lithium-ion batteries, lithium-air batteries, and other fields.

[0112] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or illustrative of the principles of the present invention and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents thereof.

Claims

1. A surface-modified oxide solid electrolyte powder, characterized in that: The surface of the surface-modified oxide solid electrolyte contains a first preset functional group; The oxide solid electrolyte includes: one or both of a crystalline electrolyte and a composite thereof and an amorphous electrolyte and a composite thereof.

2. The surface-modified oxide solid electrolyte powder according to claim 1, characterized in that: The first preset functional group includes at least one of a phenolic hydroxyl group, an amino group, an imino group, a carbon-nitrogen double bond, a carbon-nitrogen single bond, a methylene group, an ester group, a thiazolyl group and a carbonyl group; Preferably, the first preset functional group includes at least one of a phenolic hydroxyl group, an amino group, an imino group and a carbon-nitrogen single bond.

3. The surface-modified oxide solid electrolyte powder according to claim 1, characterized in that: The additives used for surface modification include: at least one of dopamine, 3,5-dichlorophenol, bis(2,4,6-trichlorophenyl)oxalate, 2,3-dimethylphenol, p-hydroxyphenylethanol, venlafaxine hydrochloride, propofol, 2-hydroxy-1-naphthaldehyde, propyl gallate, 3,4-dichlorophenol, polyethyleneimine, 1,3-benzothiazol-5-amine, 2,4-dichloroaniline, 3-bromo-1,2-diaminobenzene, (1-(4-amino-2-fluorophenyl)piperidin-4-yl)carbamic acid tert-butyl ester, 2-chloro-5-methylaniline, 2,5-dichloroaniline, 2-amino-5-chlorobenzophenone, o-bromoaniline, 4-bromo-2,6-difluoroaniline and 4-amino-2-methoxyphenol; Preferably, the additive for surface modification includes at least one of polydopamine, p-hydroxyphenylethanol, polyethyleneimine and 2,5-dichloroaniline.

4. The surface-modified oxide solid electrolyte powder according to claim 1, characterized in that: The mass fraction W1 of the additive for surface modification in the oxide solid electrolyte powder is: 0.5wt%≤W1≤15wt%, preferably 1wt%≤W1≤10wt%.

5. The surface-modified oxide solid electrolyte powder according to claim 1, characterized in that: The crystalline electrolyte includes: sodium superion conductor structure electrolyte, lithium superion conductor structure electrolyte, perovskite structure electrolyte and garnet structure electrolyte crystalline electrolyte, and the amorphous electrolyte includes: lithium phosphorus oxygen nitrogen; Preferably, the crystalline electrolyte includes: a garnet structure electrolyte.

6. The surface-modified oxide solid electrolyte powder according to claim 5, characterized in that: The garnet structure electrolyte is a lithium-containing zirconate, and its molecular formula is Li 7-x La 3-y Zr 2-z M α O 12-β D δ ; Optionally, the doping element M includes at least one of Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Sb, Bi, Se, Te, Nb, Mo, Hf, Ta, W and rare earth elements other than La, and the doping element D includes at least one of N, F, P and S, and 0≤x≤3, 0≤y≤1.5, 0≤z≤1, 0<α<3, 0≤β≤1.5, 0≤δ≤1; Preferably, the doping element M includes at least one of Mn, Fe, Co, Ni, Al, Ga, Nb, Ta, Ce, Pr, Nd, Sm, Gd, Yb and Y, and the doping element D includes at least one of F and S.

7. A method for preparing a surface-modified oxide solid electrolyte powder, characterized in that: The method for preparing the surface-modified oxide solid electrolyte powder according to any one of claims 1 to 6 comprises the following steps: Adding oxide solid electrolyte powder and an additive for surface modification into a first organic solvent to obtain an oxide solid electrolyte powder dispersion and an additive solution, respectively; The oxide solid electrolyte powder dispersion and the additive solution are fully mixed at a first preset temperature according to a first preset ratio, and then filtered, washed and dried to obtain a surface-modified oxide solid electrolyte powder.

8. The method for preparing a surface-modified oxide solid electrolyte powder according to claim 7, characterized in that: The first preset temperature is 20°C-70°C, preferably 30°C-50°C; The mixing time is 0.5h-12h, preferably 3h-8h.

9. The method for preparing a surface-modified oxide solid electrolyte powder according to claim 7, characterized in that: The temperature of the drying process is 30°C-80°C, preferably 40°C-60°C; The drying process takes 6 hours to 48 hours, preferably 12 hours to 24 hours.

10. The method for preparing a surface-modified oxide solid electrolyte powder according to claim 7, characterized in that: The mass fraction W1 of the surface modification additive in the first preset ratio to the oxide solid electrolyte powder is: 0.5wt%≤W1≤15wt%, preferably 1wt%≤W1≤10wt%.

11. The method for preparing a surface-modified oxide solid electrolyte powder according to claim 7, characterized in that: The first organic solvent includes at least one of 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 and water and a composite thereof.

12. A composite solid electrolyte, characterized in that: Its composition includes the surface-modified oxide solid electrolyte powder as described in any one of claims 1 to 6, a lithium salt and a polymer containing an ether bond, and the surface of the composite solid electrolyte contains a second preset functional group.

13. The composite solid electrolyte according to claim 12, characterized in that: The second preset functional group includes: one or more of phenolic hydroxyl group, amino group, imino group, carbon-nitrogen double bond, carbon-nitrogen single bond, methylene group, amino ether bond, ester group, thiazolyl group, and carbonyl group; preferably, the second preset functional group includes: one or more of phenolic hydroxyl group, amino group, imino group, carbon-nitrogen double bond, carbon-nitrogen single bond, methylene group, and amino ether bond.

14. The composite solid electrolyte according to claim 12, characterized in that: The polymer containing ether bonds includes at least one of polyethylene oxide, polypropylene oxide, butylene oxide, polytetrahydrofuran, polymethyl ether, polyethyl ether, polypropyl ether, polybutyl ether, polyetheretherketone, polyetherketone, polyetherketoneketone and polyetheramine; Preferably, the polymer containing ether bonds includes at least one of polyethylene oxide, polypropylene oxide, butylene oxide and polymethyl ether.

15. The composite solid electrolyte according to claim 12, characterized in that: The lithium salt comprises at least one of lithium hexafluorophosphate, lithium perfluoroalkyl phosphate, lithium tetrafluorooxalate phosphate, lithium perchlorate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethylsulfonylimide) and lithium bis(fluorosulfonylimide); Preferably, the lithium salt comprises at least one of lithium bis(trifluoromethylsulfonyl)imide, lithium perchlorate and lithium difluorooxalatoborate.

16. The composite solid electrolyte according to any one of claims 12 to 15, characterized in that: The mass fraction W2 of the surface-modified oxide solid electrolyte powder in the composite solid electrolyte is: 20wt%≤W2≤90wt%, preferably 30wt%≤W2≤80wt%; The mass fraction W3 of the polymer containing ether bonds in the composite solid electrolyte is: 5wt%≤W3≤65wt%, preferably 10wt%≤W3≤50wt%; The mass fraction W4 of the lithium salt in the composite solid electrolyte is: 5wt%≤W4≤20wt%, preferably 7wt%≤W4≤18wt%.

17. A method for preparing a composite solid electrolyte, characterized in that: For preparing the composite solid electrolyte as claimed in any one of claims 12 to 16, comprising the following steps: Dissolving a polymer containing an ether bond and a lithium salt in a second organic solvent to obtain a polymer slurry containing an ether bond, dispersing the surface-modified oxide solid electrolyte powder in the second organic solvent to obtain an oxide electrolyte slurry, and fully mixing the oxide electrolyte slurry with the polymer slurry containing an ether bond in a second preset ratio to obtain a composite solid electrolyte slurry containing a surface-modified oxide solid electrolyte; The composite solid electrolyte slurry is coated on a support membrane once or multiple times, and dried at a second preset temperature for a second preset time to obtain one or more layers of a composite solid electrolyte membrane or composite solid electrolyte tape / sheet containing a surface-modified oxide electrolyte of a first preset thickness.

18. The method for preparing a composite solid electrolyte according to claim 17, characterized in that: The second organic solvent includes: acetonitrile, ethanol, propanol, isopropanol, butanol, N,N-diol At least one of methylformamide, 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 and water.

19. The method for preparing a composite solid electrolyte according to claim 17, characterized in that: The second preset temperature is 40°C-90°C, preferably 50°C-80°C; The second preset duration is 5h-48h, preferably 8h-24h.

20. The method for preparing a composite solid electrolyte according to claim 19, characterized in that: The first preset thickness of the composite solid electrolyte is 10 μm-100 μm; preferably, the thickness of the composite solid electrolyte is 20 μm-60 μm.

21. The method for preparing a composite solid electrolyte according to claim 17, characterized in that: In the second preset ratio, the mass fraction W2 of the surface-modified oxide solid electrolyte powder in the composite solid electrolyte is: 20wt%≤W2≤90wt%, preferably 30wt%≤W2≤80wt%; the mass fraction W3 of the polymer containing ether bonds in the composite solid electrolyte is: 5wt%≤W3≤65wt%, preferably 10wt%≤W3≤50wt%; the mass fraction W4 of the lithium salt in the composite solid electrolyte is: 5wt%≤W4≤20wt%, preferably 7wt%≤W4≤18wt%.

22. Use of the composite solid electrolyte according to any one of claims 12 to 16 in all-solid-state lithium metal or lithium ion batteries, semi-solid-state lithium ion batteries and lithium-air batteries.

Images