Solid electrolyte powder, low-temperature surface modification method and application

Abstract

The invention discloses solid electrolyte powder, a low-temperature surface modification method and application. The method comprises the following steps: (1) forming a metal oxide seed layer on the surface of solid electrolyte powder through atomic layer deposition at the temperature of less than or equal to 140 DEG C; (2) introducing a fluorine-containing precursor at 90-130 DEG C in a pulse mode to carry out fluorination conversion, the pulse number is 1-6, and the single pulse is lt; the interval is gt; converting the seed layer into an oxygen-fluorine co-doped surface layer in 60 seconds; and (3) depositing a non-oxide final sealing layer on the surface layer to obtain the modified solid electrolyte powder. The whole process of the method is not more than 160 DEG C, and large-scale treatment can be realized. No continuous inorganic oxide layer exists on the surface of the obtained modified powder within 1 nm, and the modified powder is provided with an F-gradient-distributed oxygen-fluorine co-doped surface layer and a non-oxide final sealing layer and has the characteristics of electron blocking, chemical stability and lithium ion transmission. The solid electrolyte powder is suitable for halide and sulfide solid electrolyte powder, the air / hydrothermal stability and the electrode interface compatibility of the solid electrolyte powder are remarkably improved, and the high capacity retention rate can be achieved when the solid electrolyte powder is used for all-solid-state lithium batteries.

Description

Technical Field

[0001] This invention relates to the field of surface modification technology for solid electrolyte materials, specifically to a solid electrolyte powder, a low-temperature surface modification method, and its application. Background Technology

[0002] With the rapid development of electric vehicles and portable electronic devices, the demand for high-energy-density and high-safety batteries is increasing. All-solid-state lithium batteries, due to their advantages such as high safety, high energy density, and long cycle life, are considered an important direction for the development of next-generation battery technology. In all-solid-state lithium batteries, the solid electrolyte is a key component, among which sulfide and halide solid electrolytes have attracted much attention due to their high ionic conductivity.

[0003] Sulfide solid electrolytes (such as Li6PS5Cl and Li6PS5Br) possess excellent room-temperature ionic conductivity, but they readily decompose and release toxic H2S gas under air / humidity conditions. Furthermore, they exhibit severe interfacial side reactions with lithium metal anode materials. Sulfide electrolytes are further weakened by the extremely low potential of Li... 0 Reduction decomposition produces S, Li3P, Li2S, and Li2X, leading to the accumulation of non-conductive decomposition products, increasing interfacial resistance, and hindering Li⁺ transport. Unstable interfaces and uneven Li deposition can cause the formation and growth of lithium dendrites, which may puncture the electrolyte, causing a short circuit. Interfacial side reactions consume active lithium and electrolyte, resulting in rapid capacity decay and low coulombic efficiency. Furthermore, redox reactions occur between sulfide electrolytes and high-voltage cathode materials, leading to LPSC structure decomposition and capacity decay. While halide solid electrolytes (such as Li3InCl6 and Li2ZrCl6) possess high oxidation stability, they cannot avoid hydrolysis. Low-conductivity materials such as LiCO3 and Li2O easily form on their surfaces. Moreover, interfacial side reactions exist when halide solid electrolytes come into contact with metallic lithium. Lithium metal can reduce high-valence cations in the electrolyte, with reduction products including Li and In / Y alloys. Due to the presence of the alloy phase, its mixed conductivity cannot passivate the interface, thus the decomposition reaction continues. Surface modification and interfacial stability optimization of halide solid electrolytes at the powder scale still face challenges.

[0004] To address the stability issues of solid-state electrolytes, existing technologies typically employ methods that form a protective coating on the powder surface. CN108539250A discloses a method for forming a coating layer on the surface of cathode material powder using atomic layer deposition (ALD), followed by high-temperature sintering (300-1000℃) to form a solid electrolyte layer. CN109244547B proposes coating a metal oxide layer onto the surface of solid electrolyte powder using ALD, followed by hot pressing at 200-1400℃, allowing metal ions to be doped into the solid electrolyte structure to prepare a composite solid-state electrolyte membrane. While these methods can improve material stability, they generally require high processing temperatures (200-300℃ or higher), which can lead to phase transitions, halogen volatilization, or uncontrolled element diffusion in heat-sensitive solid-state electrolyte materials.

[0005] CN108172891B describes a method for preparing a positive electrode active material with a fluorinated modification layer on its surface by reacting a gaseous fluorine source with a positive electrode material in a closed container. This method can avoid interfacial reactions between the positive electrode material and the sulfide-based solid electrolyte, thus reducing interfacial impedance. However, this method mainly focuses on the surface modification of the positive electrode material and does not address the surface control of the solid electrolyte powder. Interfacial side reactions still exist when the solid electrolyte powder comes into contact with lithium metal.

[0006] CN111129571A proposes a method for fabricating all-solid-state thin-film lithium batteries based on physical vapor deposition (PVD). By using a solid electrolyte sheet with high ionic conductivity as the support structure, it solves the problem of low ionic conductivity in solid electrolyte films. However, this technology is mainly suitable for thin-film batteries and is difficult to apply to the large-scale processing of powdered solid electrolytes.

[0007] In the prior art, although there are various surface modification methods to improve the stability of solid electrolytes, the following technical problems still exist: (1) Traditional oxide coatings (such as Al2O3) can improve air stability, but they often introduce high interfacial resistance, making it difficult to maintain ion flux while taking into account electronic barrier and chemical stability; (2) Existing processes generally use high temperatures (200-300℃), which may lead to material phase change, halogen volatilization and uncontrollable diffusion at depth; (3) There is a lack of systematic methods to achieve controllable shallow modification of the surface layer of solid electrolyte powder under low temperature conditions, especially for non-oxide encapsulation strategies for halide solid electrolytes; (4) Existing technologies cannot simultaneously achieve multiple requirements of electronic barrier, chemical stability and lithium ion transport, especially under the premise of maintaining the ability to process powder on a large scale.

[0008] Therefore, in response to the problems of sulfide solid electrolytes in existing technologies, such as easy decomposition and release of H2S under air / humidity conditions, and side reactions with lithium metal anodes and high-voltage cathodes, and the shortcomings of existing technologies that improve air stability by forming inorganic oxide coatings on the powder surface, which typically use a process window of 200–300℃ and may introduce high interfacial impedance, making it difficult to maintain ion flux while simultaneously achieving electronic barrier and chemical stability, there is an urgent need to develop a modification method for precise control of the solid electrolyte powder surface under low-temperature (≤160℃) conditions. This method should be able to construct a nanoscale oxygen-fluorine co-doped surface layer and achieve synergistic optimization of chemical stability, electronic barrier, and lithium-ion transport through a non-oxide final sealing layer, thereby comprehensively improving the environmental stability and electrode interface compatibility of solid electrolyte powders. Summary of the Invention

[0009] To achieve the above technical objectives, this invention provides an in-situ construction method for a 0.5–2.0 nm shallow O / F modification band on the surface of a powder under conditions of ≤160℃. A non-oxide final sealing layer is used to achieve chemical stability, electronic barrier and lithium-ion transport, thereby improving the air / humid heat stability and electrode interface compatibility of solid electrolyte powder, while also having the ability to process powder on a large scale.

[0010] One objective of this invention is to provide a low-temperature surface modification method for solid electrolyte powder, comprising the following steps: (1) Low-temperature seed layer deposition: A seed layer with a thickness of 0.3-1.5 nm is deposited on the surface of solid electrolyte powder by atomic layer deposition at ≤140℃. The seed layer can be a metal oxide layer or a metal-organic thin film. (2) Low-temperature fluorination conversion treatment: The precursor of the target fluoride is introduced in pulse mode at 90-130℃ to carry out fluorination conversion, so that the convertible seed layer is converted in situ into a metal oxide layer or metal-organic film doped with metal fluoride, that is, an M-O-F layer with a thickness of 0.3-1.5 nm is formed on the surface and subsurface of the solid electrolyte powder, and the thickness of the metal oxide layer or metal-organic film in the M-O-F layer is less than 0.5 nm. (3) Non-oxide final sealing layer deposition: Under the condition of ≤150℃, a non-oxide final sealing layer with a thickness of 1-6 nm is deposited on the powder surface after step (2) to obtain modified solid electrolyte powder; The metal-organic thin film is a hybrid thin film formed by a metal center and an organic ligand, and the metal element M in the M–O–F layer is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum.

[0011] Furthermore, the modified solid electrolyte powder does not have a continuous inorganic oxide layer with a thickness ≥ 0.5 nm within 1 nm of its surface.

[0012] Furthermore, step (1), the seed layer deposition process, includes the following steps: S1. Place the electrolyte powder into the ALD reaction chamber, or place the electrolyte powder into a porous container inside the ALD reaction chamber, and then repeatedly evacuate and replace the nitrogen gas at least three times. S2. Fluidize the electrolyte powder in the reaction chamber under a nitrogen or argon atmosphere, with a fluidization pressure of 1-1000 torr, or achieve electrolyte powder dispersion by rotating a porous container; the preferred fluidization pressure is 10-100 torr. S3. Based on the type of seed layer, select the reaction precursor and set the parameters of the ALD reaction chamber: deposition temperature 100℃-140℃, deposition pressure 0.01 torr-500 torr; S4. Introduce precursor A vapor into the ALD reaction chamber under nitrogen or argon gas, and hold for 10-300 seconds. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. S5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor A. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. S6. Under the action of the carrier gas, the precursor B is introduced into the ALD reaction chamber and held for 10-300 seconds; the carrier gas: nitrogen or argon has a flow rate of 5-8000 sccm. S7. Purge the reaction chamber with nitrogen or argon to remove excess precursor B and byproducts; Repeat steps S4 to S7 until the seed layer corresponding to precursor A reaches the set coating thickness of 0.3-1.5 nm. Furthermore, when the seed layer is a metal oxide, precursor A is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 140°C. The metal element in the metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum. Precursor B is oxygen source vapor. Preferably, the precursor A includes TMA, Mg(EtCp)2, TiCl4, Zr(NMe2)4, Y(TMHD)3, and La(TMHD)3; the precursor B is one of water, hydrogen peroxide, oxygen, ozone, or atomic oxygen.

[0013] Furthermore, when the seed layer is a metal-organic thin film, precursor A is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 140°C. The metal element in the metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum. Precursor B is an organic ligand source with a volatilization temperature not exceeding 140°C. The organic ligand source has two or more functional groups that can react with metal hydroxyl / alkoxy groups, including –OH, –COOH, and –NH2. Preferably, the precursor A includes TMA, Mg(EtCp)2, TiCl4, Zr(NMe2)4, Y(TMHD)3, and La(TMHD)3; the precursor B is one of ethylene glycol, glycerol, 1,4-butanediol, 1,6-hexanediol, hydroquinone, p-phenylenediamine, phenylglycerol, acetylene, glycidyl ether, or glycerol; more preferably, the precursor B is hydroquinone.

[0014] Furthermore, step (2) the fluorination process includes the following steps: H1. Place the solid electrolyte powder with a seed layer on its surface into the ALD reaction chamber or a porous container inside the ALD reaction chamber, and then repeatedly evacuate and replace the nitrogen gas at least three times. H2. The solid electrolyte powder with a seed layer on its surface is fluidized in the reaction chamber under a nitrogen or argon atmosphere at a fluidization pressure of 1-1000 torr, or the solid electrolyte powder with a seed layer on its surface is dispersed by rotating a porous container; the preferred fluidization pressure is 10-100 torr. H3. Set the parameters of the ALD reaction chamber: deposition temperature 90℃-130℃, deposition pressure 0.01 torr-500 torr; H4. The precursor of the target fluoride is introduced into the ALD reaction chamber under nitrogen or argon gas, and 1-6 short gas phase pulses are maintained. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm, with each pulse <10s and an interval >60s. H5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor of the target fluoride. The flow rate of the carrying gas, nitrogen or argon, is 5-8000 sccm. H6. Purge the reaction chamber with nitrogen or argon to remove excess precursors and byproducts of the target fluoride, converting a portion of the seed layer into a metal fluoride, i.e., converting the metal oxide or metal-organic thin film into an M–O–F layer. The M–O–F layer is a metal oxide layer or metal-organic thin film doped with metal fluoride.

[0015] Furthermore, the precursor of the target fluoride is HF-pyridine (C5H6FN) or an equivalent fluorinated precursor, triethylamine (C6H). 18 F3N,N,N-dimethylpropionamide hydrogen fluoride complex C6H 13 FN2O.

[0016] Furthermore, the non-oxide final sealing layer deposition process in step (3) includes the following steps: W1. Place the solid electrolyte powder processed in step (2) into the ALD reaction chamber or a porous container in the ALD reaction chamber, and then repeatedly evacuate and replace nitrogen gas at least three times. W2. Fluidize the solid electrolyte powder treated in step (2) in the reaction chamber under a nitrogen or argon atmosphere, with a fluidization pressure of 1-1000 torr, or achieve the dispersion effect of the solid electrolyte powder treated in step (2) by rotating the porous container; the fluidization pressure is preferably 10-100 torr. W3. Set the parameters of the ALD reaction chamber: deposition temperature 90℃-130℃, deposition pressure 0.01 torr-500 torr; W4. Introduce precursor C into the ALD reaction chamber under nitrogen or argon gas, and hold for 10-300 seconds; the flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. W5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor C. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. W6. Under the action of a carrier gas, the precursor D is introduced into the ALD reaction chamber and held for 10-300 seconds; the carrier gas is nitrogen or argon with a flow rate of 5-8000 sccm. W7. Purge the reaction chamber with nitrogen or argon to remove excess precursor D and byproducts; Repeat steps W4 to W7 until the final sealing layer deposition reaches the set coating thickness of 16 nm; The non-oxide final sealing layer is one of LiF, MgF2 or LiPON; The precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150°C, wherein the metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is lithium or magnesium. The precursor D is a precursor of the target fluoride or an integrated phosphorus and nitrogen precursor source.

[0017] Furthermore, the non-oxide final sealing layer is LiF with a thickness of 2-4 nm. The precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150℃. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is lithium, preferably LiO. t Bu, LiHMDS, Li(thd), Li(hfac), Li(Piv)(H2O), Li(acac), Li(CH2SiMe3), Li( t One or more of Bu2Cp), preferably LiO t Bu or LiHMDS; the precursor D is the precursor of the target fluoride, preferably, the precursor D is pyridine C5H6FN.

[0018] Further, the non-oxide final sealing layer is MgF2 with a thickness of 1-3 nm. Precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150°C. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is magnesium. Preferably, precursor C includes: bis(ethylcyclopentadienyl)magnesium, bis(2,2,6,6-tetramethyl-3,5-heptadecyl)magnesium, bis(N, N'-Di(sec-butylacetamidine)magnesium, bis(pentamethylcyclopentadienyl)magnesium, or one or more thereof; precursor D is a precursor of the target fluoride, preferably, precursor D includes one or more of hexafluoroacetylacetone (Hhfac), carbonyl fluoride, chlorine fluoride, 1-chloro-2,2-difluoroethylene, dichlorofluoromethane, 1-chloro-1-fluoroethane, difluoromethane, nitrogen trifluoride, pentafluoroethane, perfluorocyclohexene, trifluoroacetic acid, trifluoroethane, and trifluoroethanol.

[0019] Furthermore, the non-oxide final sealing layer is a LiPON layer with a thickness of 1-3 nm. The precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150°C. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is lithium, preferably LiO. t One of the following: Bu, LiHMDS, Li[N(SiMe2CF3)2], Li[OC(CH3)(CF3)2] (Li(hfp)), Li[Gua(Mes)], Li[AMD], Li(C5iPr5), Li(C5H4TMS) or LiiOSi(NMe2)3, preferably LiO t Bu or LiHMDS, preferably LiOt Bu or LiHMDS; precursor D is an integrated phosphorus and nitrogen precursor source, preferably one of TDMPP, phosphazene monomers, diaminophosphate, TMPA and its derivatives or BDMAP, and most preferably DEPA. Precursors for atomic layer deposition of LiPON are reported in CN110527974A.

[0020] Furthermore, the atomic layer deposition apparatus is selected from fluidized bed, continuous vibrating bed or rotary drum, and the trace O2 / H2O content is controlled at ≤10 ppm.

[0021] The second objective of this invention is to provide a solid electrolyte powder, obtained by the above method, which comprises, from the outside to the inside, a non-oxide final sealing layer, an M-O-F layer, and a solid electrolyte powder.

[0022] Furthermore, the non-oxide final sealing layer is selected from one of LiF, MgF2, or LiPON.

[0023] Furthermore, the M–O–F layer is a metal oxide layer or metal-organic thin film doped with metal fluoride, and the thickness of the metal oxide layer or metal-organic thin film in the M–O–F layer is less than 0.5 nm; the metal element M in the M–O–F layer is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum.

[0024] Furthermore, the solid electrolyte powder is a heat-sensitive solid electrolyte material; the particle size D of the solid electrolyte powder is... 50 The range is 1-20 μm.

[0025] Furthermore, the solid electrolyte powder is one of halide solid electrolyte powder or sulfide solid electrolyte powder, preferably one of Li3InCl6, Li2ZrCl6, Li3YCl6, Li6PS5Cl, Li6PS5Br, LGPS and their dopants / solid solutions.

[0026] Furthermore, the thickness of the non-oxide final encapsulation layer is 1-6 nm, and the electronic conductivity of the non-oxide final encapsulation layer at 25°C is ≤1×10⁻⁶. -10 S•cm -1 In-plane lithium-ion conductivity ≥1×10 -7 S•cm -1 .

[0027] Furthermore, the thickness of the M–O–F layer is 0.3-1.5 nm; after exposure to RH 50% / 25℃ / 24 h, the modified solid electrolyte powder exhibits the following H2S release: for sulfide powder, ≤0.5 ppm•g -1 For halide powders, Cl - Retention rate ≥ 99%.

[0028] A third objective of this invention is to provide an all-solid-state lithium battery, comprising a positive electrode, a negative electrode, and a solid electrolyte layer therebetween, wherein the solid electrolyte layer is formed by densifying the modified solid electrolyte powder or by combining it with a polymer.

[0029] Furthermore, the positive electrode material is one of the high-voltage positive electrode materials, preferably one of lithium-rich manganese-based materials, high-nickel ternary materials, or high-voltage spinel materials; the negative electrode material is lithium metal.

[0030] Furthermore, the polymer matrix is ​​one of PEO, PVDF-HFP, or polycarbonate.

[0031] Furthermore, the mass ratio of the electrolyte powder to the polymer matrix is ​​70:30 to 90:10.

[0032] The all-solid-state lithium battery provided by this invention retains ≥85% of its capacity after 200 cycles at 25°C and 0.2-0.5 C.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The entire process is ≤160℃ to avoid material phase change, halogen volatilization and uncontrollable diffusion at high temperature; the interface phase with limited depth (0.5-2.0 nm) is achieved through low temperature F-conversion, which has both electronic barrier and chemical stability, while maintaining lithium ion flux; finally, there is no continuous inorganic oxide layer (thickness <0.5 nm) within 1 nm of the surface, reducing interface polarization.

[0034] (2) The method is applicable to halide SSE powder and is also compatible with sulfide SSE powder. The powder-ALD / PE-ALD / ALI device can realize continuous and large-scale processing.

[0035] (3) The present invention achieves chemical stability, electronic barrier and lithium-ion transport by using a non-oxide final sealing layer, thereby improving the air / humid heat stability and electrode interface compatibility of solid electrolyte powder, while having the ability to process powder on a large scale. Attached Figure Description

[0036] Figure 1 This is an electron microscope image of the electrolyte powder before modification.

[0037] Figure 2 This is an electron microscope image of the modified electrolyte powder.

[0038] Figure 3 This is a schematic diagram of the surface-modified solid electrolyte powder of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] The groups represented by the names of the precursor reagents used in this invention are as follows: acac: acetylacetonate; EtCp: ethylcyclopentadienyl; hfac: hexafluoroacetylacetonate; thd / TMHD: tetramethylheptanediketone; HMDS: hexamethyldisilazyl; OtBu: tert-butoxy; hfp: hexafluorotert-butoxy; Cp: cyclopentadienyl; Cp*: pentamethylcyclopentadienyl; tBu2Cp or iPr5Cp: substituted cyclopentadienyl; NMe2: dimethylamino; AMD: amidine; Gua: guanidinyl; Mes: mesitylene; PEO: polyethylene oxide; Piv: neopentanoate; LGPS: Li 10 GeP2S 12 The solid-state electrode materials are as follows: Li3InCl6: lithium hexachloroindium oxide; Li2ZrCl6: lithium hexachlorozirconium oxide; Li3YCl6: lithium hexachloroyttrium oxide; Li6PS5Cl: lithium chlorothiophosphate; Li6PS5Br: lithium brominated thiophosphate; LGPS: lithium germanium thiophosphate. This invention provides a method for surface modification of solid electrolyte powder in some embodiments, which achieves precise surface modification of solid electrolyte powder through a multi-step process, thereby improving its performance in all-solid-state lithium batteries. The method includes the following steps: (1) Low-temperature seed layer deposition: A seed layer of thickness is deposited on the surface of solid electrolyte powder at a temperature not exceeding 140°C. The seed layer can be a metal oxide or a metal-organic thin film.

[0041] This step constructs an ultrathin, uniform, and continuous reactive precursor layer on the surface of the electrolyte powder, providing a "reaction template" and metal source for subsequent fluorination conversion. Metal oxides or metal-organic films can achieve atomic-level thickness control through techniques such as ALD (atomic layer deposition), avoiding the uneven reaction problems caused by direct fluorination on rough powder surfaces. The seed layer allows for precise control of the F element penetration depth and reaction extent. Metal-organic films are hybrid films formed by a metal center and organic ligands; organic ligands include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, hydroquinone, p-phenylenediamine, glycerol, acetylenyne, glycidyl ether, or glycerol.

[0042] The process of depositing a seed layer using atomic layer deposition includes: S1. Place the electrolyte powder into the ALD reaction chamber, or place the electrolyte powder into a porous container inside the ALD reaction chamber, and then repeatedly evacuate and replace the nitrogen gas at least three times. S2. Fluidize the electrolyte powder in the reaction chamber under a nitrogen or argon atmosphere, with a fluidization pressure of 1-1000 torr, or achieve electrolyte powder dispersion by rotating a porous container; the preferred fluidization pressure is 10-100 torr. S3. Based on the type of seed layer, select the reaction precursor and set the parameters of the ALD reaction chamber: deposition temperature 100℃-140℃, deposition pressure 0.01 torr-500 torr; S4. The precursor A vapor is introduced into the ALD reaction chamber under nitrogen or argon gas and held for 10-300 seconds. The flow rate of the carrying gas, nitrogen or argon, is 5-8000 sccm. S5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor A. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. S6. Under the action of the carrier gas, the precursor B is introduced into the ALD reaction chamber and held for 10-300 seconds; the carrier gas: nitrogen or argon has a flow rate of 5-8000 sccm. S7. Purge the reaction chamber with nitrogen or argon to remove excess oxygen vapor and byproducts; Repeat steps S4 to S7 until the seed layer corresponding to precursor A reaches the set coating thickness of 0.3-1.5 nm.

[0043] In one embodiment, when the seed layer can be converted into a metal oxide, the deposition thickness is 0.3-0.8 nm. Precursor A is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 140°C. The metal elements in the metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes are aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum. Preferably, when precursor A is selected from the components in Table 1, it can meet the requirements of volatilization temperature ≤140°C and stability. Preferably, precursor A is TMA. Precursor B is oxygen source vapor, and the oxygen source is water, hydrogen peroxide, oxygen, ozone, or atomic oxygen. Table 1 In one embodiment, when the seed layer can be converted into a metal-organic thin film, the deposition thickness is 0.5-1.5 nm. Precursor A is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes, with a volatilization temperature not exceeding 140°C. The metal elements in the metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes are aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum. Preferably, when precursor A is selected from the components in Table 1, it can meet the requirements of volatilization temperature ≤140°C and stability. Preferably, the precursor... A is TMA; precursor B is an organic ligand source with a volatilization temperature not exceeding 140°C. The organic ligand source has two or more functional groups that can react with metal hydroxyl / alkoxy groups, including –OH, –COOH, and –NH2. The organic ligand source is one of ethylene glycol, glycerol, 1,4-butanediol, 1,6-hexanediol, hydroquinone, p-phenylenediamine, phenylglycerol, acetylene, glycidyl ether, or glycerol. Preferably, precursor B is hydroquinone.

[0044] (2) Low-temperature fluorination conversion treatment: Under temperature conditions of 90-130℃, the convertible seed layer formed in step (1) is subjected to low-temperature fluorination conversion treatment with 1-6 short gas phase pulses using the precursor of the target fluoride, constructing a surface gradient layer with both chemical stability (moisture resistance, CO2 resistance) and ion conductivity, eliminating the obstruction of lithium ion transport by the continuous oxide layer. This process converts the convertible seed layer in situ into a doped metal fluoride (MF). x M is a metal oxide or organometallic film (one of aluminum, magnesium, titanium, zirconium, yttrium, or lanthanum), and an oxygen-fluorine co-doped surface layer of 0.3-1.5 nm is formed on the powder surface and subsurface. The precursors of the target fluoride include: HF-pyridine (hydrofluoride pyridine C5H6FN) or equivalent fluorine-containing precursors (hydrofluoride triethylamine C6H... 18 F3N,N,N-dimethylpropionamide hydrogen fluoride complex C6H 13 (FN2O). In this step, the duration of a single HF-pyridine pulse is less than 10 seconds, and the evacuation time after the pulse is greater than 60 seconds. This allows for control of the penetration depth of F in the substrate, avoiding excessive fluorination that could damage the electrolyte's bulk structure. Quantitative verification is then performed using XPS angle-resolved and ToF-SIMS profile analysis.

[0045] This step can specifically include: H1. Place the solid electrolyte powder with a seed layer on its surface into the ALD reaction chamber or a porous container inside the ALD reaction chamber, and then repeatedly evacuate and replace the nitrogen gas at least three times. H2. The solid electrolyte powder with a seed layer on its surface is fluidized in the reaction chamber under a nitrogen or argon atmosphere at a fluidization pressure of 1-1000 torr, or the solid electrolyte powder with a seed layer on its surface is dispersed by rotating a porous container; the preferred fluidization pressure is 10-100 torr. H3. Set the parameters of the ALD reaction chamber: deposition temperature 90℃-130℃, deposition pressure 0.01 torr-500 torr; H4. The precursor of the target fluoride is introduced into the ALD reaction chamber under nitrogen or argon gas, and 1-6 short gas phase pulses are maintained. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. Preferably, when the precursor of the target fluoride is HF-pyridine, the flow rate of the carrier gas N2 is 50 sccm, and the deposition pressure increases by 5 torr during the pipeline pulse gas inlet.

[0046] H5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor of the target fluoride. The flow rate of the carrying gas, nitrogen or argon, is 5-8000 sccm. H6. Purge the reaction chamber with nitrogen or argon to remove excess precursors and byproducts of the target fluoride; A portion of the seed layer is converted into a metal fluoride, that is, a metal oxide or metal-organic thin film is converted into an M–O–F layer, which is a doped MF layer. x Metal oxide layers or metal-organic thin films.

[0047] (3) Non-oxide final sealing layer deposition: Under the condition of temperature not exceeding 150℃, a non-oxide final sealing layer with a thickness of 1-6 nm is deposited on the powder surface after step (2). The non-oxide final sealing layer can be selected from LiF, MgF2 or LiPON, wherein LiF / MgF2 provides electronic insulation and chemical passivation, and LiPON further optimizes ion conduction and interface wettability.

[0048] This step can specifically include: W1. Place the solid electrolyte powder processed in step (2) into the ALD reaction chamber or a porous container in the ALD reaction chamber, and then repeatedly evacuate and replace nitrogen gas at least three times. W2. Fluidize the solid electrolyte powder treated in step (2) in the reaction chamber under a nitrogen or argon atmosphere, with a fluidization pressure of 1-1000 torr, or achieve the dispersion effect of the solid electrolyte powder treated in step (2) by rotating the porous container; the fluidization pressure is preferably 10-100 torr. W3. Set the parameters of the ALD reaction chamber: deposition temperature 90℃-130℃, deposition pressure 0.01 torr-500 torr; W4. Introduce precursor C into the ALD reaction chamber under nitrogen or argon gas, and hold for 10-300 seconds; the flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. W5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor C. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. W6. Under the action of a carrier gas, the precursor D is introduced into the ALD reaction chamber and held for 10-300 seconds; the carrier gas is nitrogen or argon with a flow rate of 5-8000 sccm. W7. Purge the reaction chamber with nitrogen or argon to remove excess precursor D and byproducts; Repeat steps W4 to W7 until the final sealing layer deposition reaches the set coating thickness of 16 nm.

[0049] In one embodiment, the non-oxide final capping layer is LiF with a thickness of 2-4 nm. The precursor C is one or a mixture of several volatile metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes, wherein the metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is lithium. The precursor C includes: LiO. t Bu, LiHMDS, Li(thd), Li(hfac), Li(Piv)(H2O), Li(acac), Li(CH2SiMe3) or Li( t Bu2Cp), the precursor C is preferably LiO. t Bu or LiHMDS, with precursor D being the precursor of the target fluoride, preferably, precursor D is pyridine hydrofluoride C5H6FN.

[0050] In one embodiment, the non-oxide final sealing layer is MgF2 with a thickness of 1-3 nm. Precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150°C. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is magnesium. Preferably, precursor C includes: bis(ethylcyclopentadienyl)magnesium, bis(2,2,6,6-tetramethyl-3,5-heptadecyl)magnesium, bis(N, When N'-di(sec-butylacetamidine)magnesium, bis(pentamethylcyclopentadienyl)magnesium, or a combination of two or more of these gases are present, atomic layer deposition (ALD) can be carried out at a temperature not exceeding 150°C. Precursor D is a precursor of the target fluoride. Preferably, precursor D includes hexafluoroacetylacetone (Hhfac), carbonyl fluoride, chlorine fluoride, 1-chloro-2,2-difluoroethylene, dichlorofluoromethane, 1-chloro-1-fluoroethane, difluoromethane, nitrogen trifluoride, pentafluoroethane, perfluorocyclohexene, trifluoroacetic acid, trifluoroethane, trifluoroethanol, or a combination of two or more of these gases, ALD can be carried out at a temperature not exceeding 150°C. Precursors for ALD of MgF2 are reported in JP2022542507A.

[0051] In one embodiment, the non-oxide final capping layer is a LiPON layer with a thickness of 1-3 nm. The precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150°C. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is lithium. The precursor C includes: LiO t Bu, LiHMDS, Li(thd), Li(hfac), Li(Piv)(H2O), Li(acac), Li(CH2SiMe3) or Li( t Bu2Cp), the precursor C is preferably LiO. t Bu or LiHMDS, these precursors can undergo atomic layer deposition reactions at temperatures not exceeding 150°C. Precursor D is an integrated phosphorus and nitrogen precursor source, including DEPA, (NH4)3PO4, and C6H 18 N3OP or C 10 H 19 ClNO5P; preferably DEPA or (NH4)3PO4. These precursors can be subjected to atomic layer deposition reactions at temperatures not exceeding 150°C. Relevant precursors for atomic layer deposition of LiPON are reported in CN110527974A.

[0052] The solid electrolyte powder obtained after the above three steps does not have a continuous inorganic oxide layer with a thickness of ≥0.5 nm within 1 nm of its surface. This gives the modified powder excellent properties of electronic barrier, chemical stability and lithium-ion transport.

[0053] The surface modification method for solid electrolyte powder provided in the above embodiments has a maximum temperature of no more than 160°C throughout the entire modification process, and is suitable for heat-sensitive solid electrolyte materials and particle sizes D. 50 It consists of various solid electrolyte powders ranging from 1 to 20 μm.

[0054] In some embodiments, the solid electrolyte powder is a halide solid electrolyte powder selected from Li3InCl6, Li2ZrCl6, Li3YCl6 and their dopants / solid solutions.

[0055] In some embodiments, the solid electrolyte powder is a sulfide solid electrolyte powder selected from Li6PS5Cl, Li6PS5Br, LGPS and their dopants / solid solutions.

[0056] Furthermore, the electrolyte powder before modification had uneven particle size (with obvious large particles) and severe agglomeration, forming secondary particle clusters (see...). Figure 1 Due to its high surface energy and lack of stable interfacial protection, it is prone to agglomeration. The modified electrolyte powder exhibits significantly reduced particle size and uniform distribution, with good dispersibility (no significant agglomeration) (see...). Figure 2 This aligns with the expected effect of modified materials reducing surface energy and suppressing interparticle interactions through surface coatings (such as non-oxide final sealing layers and Al-OF layers). When used in all-solid-state lithium batteries, the modified solid electrolyte powder significantly improves air / humid heat stability and electrode interface compatibility, effectively solving the stability and interface problems faced by traditional solid electrolytes in battery applications. This method features low processing temperature, flexible material selection, and suitability for continuous powder processing, demonstrating broad application prospects in the large-scale modification of solid electrolyte powders and the industrialization of all-solid-state batteries.

[0057] The modified solid electrolyte powder prepared through the above embodiments, such as Figure 3 The structure, from the outside in, includes a non-oxide final sealing layer, an M–O–F layer, and a solid electrolyte powder. The non-oxide final sealing layer is selected from LiF, MgF2, or LiPON. The M–O–F layer is a metal oxide layer or metal-organic film doped with metal fluorides. The thickness of the metal oxide layer or metal-organic film in the M–O–F layer is less than 0.5 nm, and the thickness of the M–O–F layer is 0.3-1.5 nm. The solid electrolyte powder is a heat-sensitive solid electrolyte material, including Li3InCl6, Li2ZrCl6, Li3YCl6, and their dopants / solid solutions.

[0058] Particle size D of solid electrolyte powder 50 The range is 1-20 μm.

[0059] Example 1 The modified solid electrolyte powders prepared using the above surface modification methods are as follows: From the outside in, it includes a non-oxide final sealing layer, an Al–O–F layer, and a solid electrolyte powder. The non-oxide final sealing layer is selected from LiF. The Al–O–F layer is an aluminum metal-organic thin film doped with AlF3. The thickness of the aluminum metal-organic thin film in the Al–O–F layer is less than 0.5 nm. The thickness of the Al–O–F layer is 0.8 nm. The solid electrolyte powder is a heat-sensitive solid electrolyte material, including Li3InCl6.

[0060] Particle size D of solid electrolyte powder 50 It is 3.76 μm.

[0061] Example 2 The modified solid electrolyte powders prepared using the above surface modification methods are as follows: From the outside to the inside, it includes a non-oxide final sealing layer, an Al–O–F layer, and a solid electrolyte powder. The non-oxide final sealing layer is selected from LiPON. The Al–O–F layer is an aluminum metal-organic thin film doped with AlF3. The thickness of the aluminum metal-organic thin film in the Al–O–F layer is less than 0.5 nm. The thickness of the Al–O–F layer is 1 nm. The solid electrolyte powder is a heat-sensitive solid electrolyte material, including Li2ZrCl6.

[0062] Particle size D of solid electrolyte powder 50 It is 5.42 μm.

[0063] Example 3 The modified solid electrolyte powders prepared using the above surface modification methods are as follows: From the outside in, it includes a non-oxide final sealing layer, an Al–O–F layer, and a solid electrolyte powder. The non-oxide final sealing layer is selected from MgF2. The Al–O–F layer is an aluminum metal-organic thin film doped with AlF3. The thickness of the aluminum metal-organic thin film in the Al–O–F layer is less than 0.5 nm. The thickness of the Al–O–F layer is 1.5 nm. The solid electrolyte powder is a heat-sensitive solid electrolyte material, including Li3YCl6.

[0064] Particle size D of solid electrolyte powder 50 It is 4.63 μm.

[0065] Example 4 The modified solid electrolyte powders prepared using the above surface modification methods are as follows: From the outside to the inside, it includes a non-oxide final sealing layer, an Al–O–F layer, and a solid electrolyte powder. The non-oxide final sealing layer is selected from LiF. The Al–O–F layer is an Al2O3 layer doped with AlF3. The thickness of the aluminum metal-organic film in the Al–O–F layer is less than 0.5 nm. The thickness of the Al–O–F layer is 1 nm. The solid electrolyte powder is a heat-sensitive solid electrolyte material, including Li2ZrCl6.

[0066] Particle size D of solid electrolyte powder 50 It is 2.86 μm.

[0067] The modified solid electrolyte powder prepared through the above embodiments has the following characteristics: (1) The oxygen-fluorine co-doped surface layer exhibits detectable F under AR-XPS or ToF-SIMS and has Al-F / Al-OF characteristic peaks. The presence of this F element distribution and characteristic peaks proves the formation of the modification band, which acts as a buffer and protector between the powder surface layer and the subsurface layer. The non-oxide final seal layer has extremely low electronic conductivity at 25°C, not exceeding 1×10⁻⁶. -10 S•cm -1 At the same time, it maintains a high in-plane lithium-ion conductivity, not less than 1×10 -7 S•cm -1 These electrical properties ensure that the modified solid electrolyte powder can effectively block electron conduction in lithium-ion batteries while allowing lithium ions to migrate rapidly, thereby improving the battery's energy density and safety.

[0068] (2) After exposure for 24 hours at a relative humidity of 50% and a temperature of 25°C: for sulfide powder, the H2S release does not exceed 0.5 ppm•g -1 For halide powders, Cl - The retention rate is no less than 99%. This indicates that the modified solid electrolyte powder has excellent moisture resistance and chemical stability, which greatly reduces the safety risks and material loss when handled in air.

[0069] (3) By eliminating the continuous inorganic oxide layer within 1 nm of the surface, the problem of increased interfacial impedance that may be caused by traditional oxide protective layers is avoided. The presence of the oxygen-fluorine co-doped surface layer protects the internal electrolyte from environmental influences while maintaining good ion conductivity. The outermost non-oxide final sealing layer further enhances the stability and electrochemical performance of the powder. This multi-layered surface modification structure enables the solid electrolyte powder to maintain excellent electrochemical performance while significantly improving environmental stability and processing safety, providing an important material basis for the practical application of solid-state batteries. As shown in Table 2.

[0070] Table 2 In some embodiments, an all-solid-state lithium battery is provided, comprising a positive electrode, a negative electrode, and a solid electrolyte layer therebetween. The solid electrolyte layer in the all-solid-state lithium battery is formed by densifying or compositing the modified solid electrolyte powder, which has specific structural characteristics, including the absence of a continuous inorganic oxide layer within 1 nm of its surface; an oxygen- and fluorine-containing co-doped surface layer with a thickness of 0.3-1.5 nm in the powder surface and subsurface layers; and an outermost non-oxide final sealing layer of 1-6 nm, such as LiF, MgF2, or LiPON.

[0071] In some embodiments, the negative electrode of the all-solid-state lithium battery is made of lithium metal, and the positive electrode is made of a high-voltage positive electrode material with a charging cut-off voltage ≥4.4 V. This high-voltage positive electrode material can be a lithium-rich manganese-based material, a high-nickel ternary material, or a high-pressure spinel material, capable of stable operation under high voltage conditions and improving the battery's energy density. During battery assembly, the modified solid electrolyte powder is first densified to form a solid electrolyte layer through cold pressing or hot pressing processes, with a pressure range of 100-500 MPa and a hot pressing temperature not exceeding 150°C. Alternatively, the modified solid electrolyte powder is composited with a polymer matrix to form a composite solid electrolyte layer. The polymer matrix can be materials such as PEO, PVDF-HFP, or polycarbonate, with a mass ratio of electrolyte powder to polymer of 70:30 to 90:10.

[0072] In a preferred embodiment, the high-voltage cathode material used in the all-solid-state lithium battery is LiNi. 0.8 Co 0.1 Mn 0.1 The O2-modified solid electrolyte powder was specifically prepared in Example 1. The negative electrode material was a lithium battery with a charging cut-off voltage of 4.5 V. After 200 cycles at 25°C and 0.2 C, the capacity retention rate reached 88%.

[0073] In another preferred embodiment, the high-voltage cathode material used in the all-solid-state lithium battery is LiMn. 1.5 Ni 0.5 The O4 modified solid electrolyte powder was specifically prepared in Example 2. The negative electrode material was a lithium battery with a charging cut-off voltage of 4.8 V. After 200 cycles at 25°C and 0.3 C, the capacity retention rate reached 87%.

[0074] In yet another preferred embodiment, the all-solid-state lithium battery uses Li as the high-voltage cathode material. 1.2 Mn 0.54 Ni 0.13 Co 0.13The O2-modified solid electrolyte powder was specifically prepared in Example 3. The negative electrode material was a lithium battery with a charging cut-off voltage of 4.6 V. After 200 cycles at 25°C and 0.5 C, the capacity retention rate reached 85%.

[0075] In one comparative example, the high-voltage cathode material used in the all-solid-state lithium battery is LiNi. 0.8 Co 0.1 Mn 0.1 O2, the solid electrolyte powder is the unmodified solid electrolyte, other battery assembly conditions are the same as in the preferred embodiment, the charging cut-off voltage is 4.5 V, and the capacity retention rate is 74% after 200 cycles at 25°C and 0.2 C.

[0076] The battery performance test results of the above embodiments and comparative examples are shown in Table 3. It can be seen that the all-solid-state lithium battery provided in the above embodiments has a capacity retention rate of ≥85% after 200 cycles at 25℃ and 0.2-0.5 C, demonstrating excellent cycle stability. This excellent cycle performance is mainly attributed to the special structural design of the modified solid electrolyte powder, especially the improvement of electrolyte / electrode interface stability by the surface modification layer.

[0077] Table 3 In summary, the all-solid-state lithium battery provided by this invention has the following advantages: First, by using modified solid electrolyte powder, the environmental stability and electrochemical stability of the electrolyte layer are significantly improved; second, the combination of lithium metal anode and high-voltage cathode material enables the battery to have high energy density; finally, the battery exhibits excellent cycle stability at room temperature, providing possibilities for the practical application of all-solid-state lithium batteries.

[0078] Finally, it should be noted that the above descriptions are merely preferred embodiments of this application, and this application is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of this application should be considered to be included within the protection scope of this application.

Claims

1. A modified solid electrolyte powder, characterized in that, From the outside to the inside, it includes a non-oxide final sealing layer, an M–O–F layer, and solid electrolyte powder; The non-oxide final sealing layer is selected from one of LiF, MgF2 or LiPON; The M–O–F layer is a metal oxide layer or metal-organic thin film doped with metal fluoride, and the thickness of the metal oxide layer or metal-organic thin film in the M–O–F layer is less than 0.5 nm; the metal element M in the M–O–F layer is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum; The solid electrolyte powder is a heat-sensitive solid electrolyte material.

2. The modified solid electrolyte powder according to claim 1, characterized in that, The thickness of the non-oxide final sealing layer is 1-6 nm, and the electronic conductivity of the non-oxide final sealing layer at 25°C is ≤1×10⁻⁶. -10 S•cm -1 In-plane lithium-ion conductivity ≥1×10 -7 S•cm -1 .

3. The modified solid electrolyte powder according to claim 1, characterized in that, The solid electrolyte powder particle size D 50 The range is 1-20 μm.

4. The modified solid electrolyte powder according to claim 1, characterized in that, The thickness of the M–O–F layer is 0.3-1.5 nm.

5. A method for low-temperature surface modification of solid electrolyte powder, used to prepare the modified solid electrolyte powder as described in any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Low-temperature seed layer deposition: A seed layer with a thickness of 0.3-1.5 nm is deposited on the surface of solid electrolyte powder by atomic layer deposition at ≤140℃. The seed layer can be a metal oxide layer or a metal-organic thin film. (2) Low-temperature fluorination conversion treatment: The precursor of the target fluoride is introduced in pulse mode at 90-130℃ to carry out fluorination conversion, so that the convertible seed layer is converted in situ into a metal oxide layer or metal-organic film doped with metal fluoride, that is, an M-O-F layer with a thickness of 0.3-1.5 nm is formed on the surface and subsurface of the solid electrolyte powder, and the thickness of the metal oxide layer or metal-organic film in the M-O-F layer is less than 0.5 nm. (3) Non-oxide final sealing layer deposition: Under the condition of ≤150℃, a non-oxide final sealing layer with a thickness of 1-6 nm is deposited on the powder surface after step (2) to obtain modified solid electrolyte powder; The metal-organic thin film is a hybrid thin film formed by a metal center and an organic ligand, and the metal element M in the M–O–F layer is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum.

6. The method according to claim 5, characterized in that, Step (1) The seed layer deposition process includes the following steps: S1. Place the electrolyte powder into the ALD reaction chamber, or place the electrolyte powder into a porous container inside the ALD reaction chamber, and then repeatedly evacuate and replace the nitrogen gas at least three times. S2. Fluidize the electrolyte powder in the reaction chamber under a nitrogen or argon atmosphere, with a fluidization pressure of 1-1000 torr, or achieve electrolyte powder dispersion by rotating a porous container; the preferred fluidization pressure is 10-100 torr. S3. Based on the type of seed layer, select the reaction precursor and set the parameters of the ALD reaction chamber: deposition temperature 100℃-140℃, deposition pressure 0.01 torr-500 torr; S4. Introduce precursor A vapor into the ALD reaction chamber under nitrogen or argon gas, and hold for 10-300 seconds. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. S5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor A. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. S6. Under the action of the carrier gas, the precursor B is introduced into the ALD reaction chamber and held for 10-300 seconds; the carrier gas: nitrogen or argon has a flow rate of 5-8000 sccm. S7. Purge the reaction chamber with nitrogen or argon to remove excess precursor B and byproducts; Repeat steps S4 to S7 until the seed layer corresponding to precursor A reaches the set coating thickness of 0.3-1.5 nm. When the seed layer is a metal oxide, precursor A is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 140°C. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, and metal β-diketone complex is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum. Precursor B is oxygen source vapor. When the seed layer is a metal-organic thin film, precursor A is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 140°C. The metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, and metal β-diketone complex is one of aluminum, magnesium, titanium, zirconium, yttrium, and lanthanum. Precursor B is an organic ligand source with a volatilization temperature not exceeding 140°C. The organic ligand source has two or more functional groups that can react with metal hydroxyl / alkoxy groups, including –OH, –COOH, and –NH2.

7. The method according to claim 6, characterized in that, The precursor A includes TMA, Mg(EtCp)2, TiCl4, Zr(NMe2)4, Y(TMHD)3, and La(TMHD)3.

8. The method according to claim 5, characterized in that, Step (2) fluorination process includes the following steps: H1. Place the solid electrolyte powder with a seed layer on its surface into the ALD reaction chamber or a porous container inside the ALD reaction chamber, and then repeatedly evacuate and replace the nitrogen gas at least three times. H2. The solid electrolyte powder with a seed layer on its surface is fluidized in the reaction chamber under a nitrogen or argon atmosphere at a fluidization pressure of 1-1000 torr, or the solid electrolyte powder with a seed layer on its surface is dispersed by rotating a porous container; the preferred fluidization pressure is 10-100 torr. H3. Set the parameters of the ALD reaction chamber: deposition temperature 90℃-130℃, deposition pressure 0.01 torr-500 torr; H4. The precursor of the target fluoride is introduced into the ALD reaction chamber under nitrogen or argon gas, and 1-6 short gas phase pulses are maintained. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm, with each pulse <10s and an interval >60s. H5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor of the target fluoride. The flow rate of the carrying gas, nitrogen or argon, is 5-8000 sccm. H6. Purge the reaction chamber with nitrogen or argon to remove excess precursors and byproducts of the target fluoride, and convert a portion of the seed layer into a metal fluoride, i.e., convert the metal oxide or metal-organic thin film into an M–O–F layer. The M–O–F layer is a metal oxide layer or metal-organic thin film doped with metal fluoride. The precursor of the target fluoride is HF-pyridine hydrofluoric acid (C5H6FN) or an equivalent fluorine-containing precursor, triethylamine hydrofluoric acid (C6H). 18 F3N,N,N-dimethylpropionamide hydrogen fluoride complex C6H 13 FN2O.

9. The method according to claim 5, characterized in that, The non-oxide final sealing deposition process in step (3) includes the following steps: W1. Place the solid electrolyte powder processed in step (2) into the ALD reaction chamber or a porous container in the ALD reaction chamber, and then repeatedly evacuate and replace nitrogen gas at least three times. W2. Fluidize the solid electrolyte powder treated in step (2) in the reaction chamber under a nitrogen or argon atmosphere, with a fluidization pressure of 1-1000 torr, or achieve the dispersion effect of the solid electrolyte powder treated in step (2) by rotating the porous container; the fluidization pressure is preferably 10-100 torr. W3. Set the parameters of the ALD reaction chamber: deposition temperature 90℃-130℃, deposition pressure 0.01 torr-500 torr; W4. Introduce precursor C into the ALD reaction chamber under nitrogen or argon gas, and hold for 10-300 seconds; the flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. W5. Purge the reaction chamber with nitrogen or argon to remove the remaining precursor C. The flow rate of the carrier gas, nitrogen or argon, is 5-8000 sccm. W6. Under the action of a carrier gas, the precursor D is introduced into the ALD reaction chamber and held for 10-300 seconds; the carrier gas is nitrogen or argon with a flow rate of 5-8000 sccm. W7. Purge the reaction chamber with nitrogen or argon to remove excess precursor D and byproducts; Repeat steps W4 to W7 until the final sealing layer deposition reaches the set coating thickness of 16 nm; The non-oxide final sealing layer is one of LiF, MgF2 or LiPON; The precursor C is one or a mixture of several of the following: metal alkylamino salts, organometallic compounds, halides, alkoxides, and metal β-diketone complexes with a volatilization temperature not exceeding 150°C, wherein the metal element in the metal alkylamino salt, organometallic compound, halide, alkoxide, or metal β-diketone complex is lithium or magnesium. Precursor D is a precursor of the target fluoride or an integrated phosphorus and nitrogen precursor source.

10. The method according to claim 9, characterized in that, The precursor C includes: LiO t Bu, LiHMDS, Li(thd), Li(hfac), Li(Piv)(H2O), Li(acac), Li(CH2SiMe3), Li( t One or more of the following: Bu2Cp, bis(ethylcyclopentadienyl)magnesium, bis(2,2,6,6-tetramethyl-3,5-heptanedione)magnesium, bis(N,N'-bis(sec-butylacetamidine)magnesium, and bis(pentamethylcyclopentadienyl)magnesium.

11. The method according to claim 9, characterized in that, The precursor D includes one or more of the following: hexafluoroacetylacetone (Hhfac), carbonyl fluoride, chlorine fluoride, 1-chloro-2,2-difluoroethylene, dichlorofluoromethane, 1-chloro-1-fluoroethane, difluoromethane, nitrogen trifluoride, pentafluoroethane, perfluorocyclohexene, trifluoroacetic acid, trifluoroethane, and trifluoroethanol.

12. A fully solid-state lithium battery, characterized in that, It includes a positive electrode, a negative electrode, and a solid electrolyte layer therebetween, wherein the solid electrolyte layer is formed by densifying or combining the modified solid electrolyte powder according to any one of claims 1 to 5 or the modified solid electrolyte powder prepared by any one of claims 6 to 11 with a polymer.

13. The all-solid-state lithium battery according to claim 12, characterized in that, The positive electrode material is one of lithium-rich manganese-based material, high-nickel ternary material, or high-pressure spinel material; the negative electrode material is lithium metal.

14. The all-solid-state lithium battery according to claim 12, characterized in that, The polymer matrix is ​​one of PEO, PVDF-HFP or polycarbonate; the mass ratio of the electrolyte powder to the polymer matrix is ​​70:30 to 90:10.

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