An oxyfluoride solid-state electrolyte composite material, and a preparation method and application thereof

Abstract

This invention relates to an oxyfluoride solid electrolyte composite material, its preparation method, and its application. The oxyfluoride solid electrolyte composite material comprises: an oxyfluoride-based solid electrolyte phase and a hydroxyapatite phase; the oxyfluoride-based solid electrolyte phase has the general chemical formula Li. 2‑x La (1+x) / 3 Nb₂O₆F, 0.7≤x≤1; In the oxyfluoride solid electrolyte composite material, the mass percentage of hydroxyapatite phase is 5wt.%~40wt.%, and the mass percentage of oxyfluoride solid electrolyte phase is 60wt.%~95wt.%; The hydroxyapatite phase and the oxyfluoride solid electrolyte phase are connected at the interface through Ca-O bonds and / or hydrogen bonds.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte technology, and in particular to an oxyfluoride solid electrolyte composite material, its preparation method, and its application. Background Technology

[0002] As all-solid-state batteries develop towards higher energy density and higher safety, the solid electrolyte, as a component in all-solid-state batteries used to conduct lithium ions and separate the positive and negative electrodes, has a significant impact on the cycle performance and safety performance of all-solid-state batteries due to its ion conduction performance, mechanical properties, and interfacial stability with the electrodes.

[0003] Existing solid electrolytes mainly include oxide solid electrolytes, sulfide solid electrolytes, and polymer solid electrolytes. Among them, oxide solid electrolytes generally have good mechanical strength and air stability, but the solid-solid interface contact between them and the electrode needs to be improved; sulfide solid electrolytes generally have high ionic conductivity, but they are relatively sensitive to air and moisture; polymer solid electrolytes have a certain degree of flexibility and interfacial adaptability, but their room temperature ionic conductivity and mechanical strength still have room for improvement.

[0004] Oxyfluoride solid electrolytes, by introducing fluorine into oxide solid electrolytes, allow for the modification of the material's crystal structure, ion transport properties, and interfacial properties. However, even after being fabricated into solid electrolyte sheets, layers, or films, oxyfluoride solid electrolytes may still exhibit issues such as high brittleness, insufficient mechanical strength, and susceptibility to cracking or breakage when the thickness is reduced. Furthermore, when oxyfluoride solid electrolytes are in direct contact with electrodes, further improvements are needed in their interfacial contact state and interfacial stability.

[0005] Hydroxyapatite possesses a stable calcium phosphate structure and certain mechanical strength, making it suitable for structural support in composite materials. However, hydroxyapatite's own lithium-ion conductivity is relatively limited. Simply mixing hydroxyapatite particles with a solid electrolyte may disrupt the continuous contact between the solid electrolyte phases, increasing the tortuosity of the lithium-ion transport path and thus affecting the ion conductivity of the composite material.

[0006] Therefore, the key technical problem to be solved by this invention is how to introduce the hydroxyapatite phase into the oxyfluorine solid electrolyte and rationally control the content, morphology, spatial distribution and interfacial connection relationship of the two phases so that the hydroxyapatite phase can improve the structural stability of the composite material and reduce its influence on lithium ion transport in the oxyfluorine solid electrolyte phase. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing an oxyfluoride solid electrolyte composite material, its preparation method, and its applications. This invention improves the bonding stability between the two phases by controlling the content, spatial distribution, and interfacial connectivity of the oxyfluoride solid electrolyte phase and the hydroxyapatite phase. The three-dimensional network structure formed by the hydroxyapatite nanowires supports the oxyfluoride solid electrolyte phase and allows it to fill the network pores, which is beneficial for improving the structural stability of the composite material and maintaining the continuous distribution of the oxyfluoride solid electrolyte phase.

[0008] To achieve the above objectives, in a first aspect, the present invention provides an oxyfluoride solid electrolyte composite material, comprising: an oxyfluoride solid electrolyte phase and a hydroxyapatite phase; The general chemical formula of the oxyfluorine-based solid electrolyte phase is Li 2-x La (1+x) / 3 Nb₂O₆F, 0.7≤x≤1; In the oxyfluoride solid electrolyte composite material, the hydroxyapatite phase accounts for 5 wt.% to 40 wt.% by mass, and the oxyfluoride solid electrolyte phase accounts for 60 wt.% to 95 wt.% by mass. The hydroxyapatite phase and the oxyfluorine-based solid electrolyte phase are connected at an interface through Ca-O bonds and / or hydrogen bonds.

[0009] Preferably, the chemical formula of the hydroxyapatite is Ca. 10 (PO4)6(OH)2; Alternatively, the hydroxyapatite is fluorinated hydroxyapatite with the chemical formula Ca. 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2; wherein, the fluorine atoms on the surface of the fluorinated hydroxyapatite and the fluorine atoms in the oxyfluorine solid electrolyte phase form F···F interactions.

[0010] More preferably, the oxyfluoride solid electrolyte composite material has a three-dimensional network filled structure; The hydroxyapatite phase is in the form of nanowires with a diameter of 50-200 nm and an aspect ratio of ≥30. Multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure; the oxyfluorine-based solid electrolyte phase fills the network pores of the three-dimensional network structure.

[0011] More preferably, the oxyfluoride solid electrolyte composite material has a core-shell structure; The oxygen-fluorine solid electrolyte phase forms the core, and the hydroxyapatite phase forms the shell. The thickness of the shell layer is 5-100 nm; The shell is a porous shell with multiple pores that penetrate the shell and / or are interconnected to form lithium-ion transport channels.

[0012] In a second aspect, embodiments of the present invention provide a method for preparing the oxyfluoride solid electrolyte composite material described in the first aspect, comprising: Preparation of hydroxyapatite nanowires; the chemical formula of the hydroxyapatite is Ca. 10 (PO4)6(OH)2 or Ca 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2; The hydroxyapatite nanowires are dispersed in a solvent, and an oxyfluorine solid electrolyte precursor or oxyfluorine solid electrolyte powder is added and mixed to obtain a mixed dispersion. The solvent in the mixed dispersion is removed by evaporation to obtain the composite precursor; The composite precursor is subjected to heat treatment to obtain the oxyfluoride solid electrolyte composite material.

[0013] Preferably, after dispersing the hydroxyapatite nanowires in the solvent, the method further includes: performing ultrasonic treatment for 30 min to 60 min; After adding the oxygen-fluorine solid electrolyte precursor or oxygen-fluorine solid electrolyte powder, the mixing specifically includes: stirring and mixing for 2 to 6 hours; The solvent includes one or more of ethanol, isopropanol, or deionized water; The heat treatment temperature is 600℃~900℃, and the time is 4h~12h.

[0014] Thirdly, embodiments of the present invention provide a method for preparing the oxyfluoride solid electrolyte composite material described in the first aspect above, comprising: Prepare an oxygen-fluorine solid electrolyte sol precursor solution containing lithium, lanthanum, niobium and fluorine sources; Hydroxyapatite nanowires were dispersed in the oxyfluorine-based solid electrolyte sol precursor solution to obtain a mixed sol; the chemical formula of the hydroxyapatite is Ca. 10 (PO4)6(OH)2 or Ca 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2; The mixed sol was heated and gelled to obtain a composite gel containing the hydroxyapatite nanowires; The composite gel was heat-treated at 500℃~800℃ to obtain the oxyfluoride solid electrolyte composite material.

[0015] Fourthly, embodiments of the present invention provide a method for preparing the oxyfluoride solid electrolyte composite material described in the first aspect, comprising: Oxyfluoride solid electrolyte particles are placed in a fluidized bed reactor; A reaction precursor is introduced into the fluidized bed reactor, and chemical vapor deposition or atomic layer deposition is used to deposit the reaction precursor on the surface of the oxygen-fluorine solid electrolyte particles to form a hydroxyapatite shell coating the oxygen-fluorine solid electrolyte particles, thereby obtaining an oxygen-fluoride solid electrolyte composite material with a core-shell structure. The reaction precursors include: calcium source precursors, phosphorus source precursors, hydroxyl-oxygen source precursors, and precursors including or excluding fluorine source precursors.

[0016] Fifthly, embodiments of the present invention provide a solid electrolyte component comprising: a solid electrolyte membrane, a solid electrolyte sheet, or a solid electrolyte layer; The solid electrolyte component is mainly composed of the oxyfluoride solid electrolyte composite material described in the first aspect above.

[0017] In a sixth aspect, embodiments of the present invention provide an all-solid-state lithium battery comprising the oxyfluoride solid electrolyte described in the first aspect above.

[0018] The oxyfluoride solid electrolyte composite material provided in this invention comprises an oxyfluoride solid electrolyte phase and a hydroxyapatite phase. The hydroxyapatite phase accounts for 5 wt.% to 40 wt.% by mass, and the oxyfluoride solid electrolyte phase accounts for 60 wt.% to 95 wt.% by mass. By controlling the mass ratio of the two phases, a high content of the oxyfluoride solid electrolyte phase can be maintained while introducing the hydroxyapatite phase, reducing the impact of excessively high hydroxyapatite content on the continuous distribution of the oxyfluoride solid electrolyte phase. The hydroxyapatite phase and the oxyfluoride solid electrolyte phase are connected at the interface through Ca-O bonds and / or hydrogen bonds, ensuring that the two phases are not limited to physical mixing. This improves the bonding stability of the two-phase interface and reduces interfacial separation caused by insufficient bonding between the two phases during pressing, sintering, or use of the composite material.

[0019] The oxyfluoride solid electrolyte of this invention has a three-dimensional network structure or a core-shell structure. When using a three-dimensional network structure, the hydroxyapatite nanowires intertwine to form a three-dimensional network, which provides support within the composite material and disperses local stress. The oxyfluoride solid electrolyte phase fills the network pores, which helps maintain the continuous distribution of the oxyfluoride solid electrolyte phase. When using a core-shell structure, the hydroxyapatite phase coats the surface of the oxyfluoride solid electrolyte phase, improving the surface stability and interfacial bonding stability of the oxyfluoride solid electrolyte particles. Both structures can simultaneously introduce the hydroxyapatite phase while maintaining the structural stability, interfacial stability, and lithium-ion transport performance of the composite material.

[0020] Therefore, by controlling the content, morphology, spatial distribution, and interfacial structure of the oxyfluoride solid electrolyte phase and the hydroxyapatite phase, this invention can improve the structural stability and interfacial bonding stability of the oxyfluoride solid electrolyte composite material. This composite material can be used in solid electrolyte components such as solid electrolyte sheets, solid electrolyte layers, or solid electrolyte membranes, and can be applied in all-solid-state lithium batteries. Attached Figure Description

[0021] Figure 1 The X-ray photoelectron spectroscopy analysis diagrams for embodiments 1, 2, 3, and 4 of the present invention are shown below. Figure 2 This is a comparison chart of the first charge-discharge specific capacity and first efficiency of Comparative Examples 1 and 2 and Examples 1, 2, 3, and 4 of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] This invention provides an oxyfluoride solid electrolyte composite material.

[0024] Oxyfluoride solid electrolyte composite materials include: oxyfluoride solid electrolyte phase and hydroxyapatite phase.

[0025] The general chemical formula of oxyfluorine-based solid electrolyte phases is Li 2-x La (1+x) / 3 Nb₂O₆F, 0.7≤x≤1.

[0026] In the oxyfluoride solid electrolyte composite material, the hydroxyapatite phase accounts for 5 wt.% to 40 wt.% by mass, while the oxyfluoride solid electrolyte phase accounts for 60 wt.% to 95 wt.% by mass. By controlling the mass ratio of the two phases, the oxyfluoride solid electrolyte phase can be maintained at a high content while introducing the hydroxyapatite phase, thus reducing the impact of excessively high hydroxyapatite content on the continuous distribution of the oxyfluoride solid electrolyte phase.

[0027] The hydroxyapatite phase and the oxyfluorine-based solid electrolyte phase are bonded together via Ca-O bonds and / or hydrogen bonds. The two phases are not limited to physical mixing, which helps improve the bonding stability of the two-phase interface and reduces interfacial separation caused by insufficient bonding during pressing, sintering, or use of the composite material.

[0028] Specifically, the hydroxyapatite phase consists of hydroxyapatite and / or fluorinated hydroxyapatite.

[0029] The chemical formula of hydroxyapatite is Ca. 10 (PO4)6(OH)2.

[0030] The chemical formula of fluorinated hydroxyapatite is Ca. 10 (PO4)6(OH) 2-y F y The fluorine atoms on the surface of fluorinated hydroxyapatite form F···F interactions with the fluorine atoms in the oxyfluorine-based solid electrolyte phase. This interaction can further improve the interfacial bonding between the fluorinated hydroxyapatite phase and the oxyfluorine-based solid electrolyte phase. Furthermore, the fluorinated hydroxyapatite phase has a higher ionic conductivity than unfluorinated hydroxyapatite, which helps to reduce the impact of the introduced hydroxyapatite on the overall ion transport performance of the composite material. Simultaneously, the use of fluorinated hydroxyapatite can reduce the compositional differences between the hydroxyapatite phase and the oxyfluorine-based solid electrolyte phase. The fluorine element in fluorinated hydroxyapatite also helps to form a stable LiF-rich interfacial layer at the electrode-solid electrolyte interface, thereby suppressing interfacial side reactions and improving interfacial stability.

[0031] The oxyfluoride solid electrolyte composite material of the present invention can be a three-dimensional network filled structure or a core-shell structure.

[0032] In the three-dimensional network-filled structure, the hydroxyapatite phase exists in the form of nanowires with a diameter of 50-200 nm and an aspect ratio ≥30. Multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure; the oxyfluorine-based solid electrolyte phase fills the network pores of the three-dimensional network structure. By using hydroxyapatite nanowires with the above morphology, a three-dimensional network structure spanning different regions within the composite material can be formed at a relatively low addition amount, avoiding the problems of local agglomeration or discontinuous distribution of the oxyfluorine-based solid electrolyte phase caused by using larger hydroxyapatite particles.

[0033] In the core-shell structure, an oxygen-fluorine solid electrolyte phase constitutes the core, and a hydroxyapatite phase constitutes the shell. The thickness of the shell is 5-100 nm. The shell is a porous shell with multiple pores, which penetrate the shell and / or are interconnected to form lithium-ion transport channels, enabling lithium ions to be transported inside and outside the shell through the pores, thereby reducing the obstruction of the continuous and dense shell to ion transport between the oxygen-fluorine solid electrolyte core and the external material.

[0034] The following preparation methods can be used to prepare the oxyfluoride solid electrolyte composite material of the present invention.

[0035] Method 1: Preparation of oxyfluoride solid electrolyte composite materials with a three-dimensional network-filled structure. The main method steps include: Step 110: Prepare hydroxyapatite nanowires; The chemical formula of hydroxyapatite is Ca. 10 (PO4)6(OH)2 or Ca 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2.

[0036] Step 120: Disperse hydroxyapatite nanowires in a solvent, add oxyfluorine solid electrolyte precursor or oxyfluorine solid electrolyte powder, and mix to obtain a mixed dispersion. Specifically, the amount of hydroxyapatite nanowires added to the oxyfluoride solid electrolyte precursor or oxyfluoride solid electrolyte powder is determined based on the mass percentage of the hydroxyapatite phase in the obtained oxyfluoride solid electrolyte composite material being 5 wt.% to 40 wt.% and the mass percentage of the oxyfluoride solid electrolyte phase being 60 wt.% to 95 wt.%.

[0037] Oxyfluorine-based solid electrolyte precursors include lithium sources, lanthanum sources, niobium sources, and fluorine sources. Specifically, lithium sources include one or more of lithium nitrate, lithium acetate, lithium hydroxide, lithium carbonate, or lithium alkoxides; lanthanum sources include one or more of lanthanum nitrate, lanthanum acetate, lanthanum chloride, or lanthanum alkoxides; niobium sources include one or more of niobium pentachloride, niobium pentaethoxy, niobium ammonium oxalate, niobium oxide, or niobate; and fluorine sources include one or more of lithium fluoride, ammonium fluoride, ammonium hydrogen fluoride, trifluoroacetic acid, or metallic trifluoroacetate.

[0038] Solvents include one or more of ethanol, isopropanol, or deionized water.

[0039] After dispersing hydroxyapatite nanowires in a solvent, before adding oxyfluorine-based solid electrolyte precursors or oxyfluorine-based solid electrolyte powders, it is preferable to perform ultrasonic treatment for 30 to 60 minutes to ensure that the hydroxyapatite nanowires are uniformly dispersed in the solvent.

[0040] After adding the oxyfluorine-based solid electrolyte precursor or oxyfluorine-based solid electrolyte powder, it is preferable to use a stirring method for 2 to 6 hours to distribute the oxyfluorine-based solid electrolyte precursor or oxyfluorine-based solid electrolyte powder between the hydroxyapatite nanowires.

[0041] Step 130: Evaporate to remove the solvent from the mixed dispersion to obtain the composite precursor; Specifically, in one embodiment, the temperature for evaporating and removing the solvent from the mixed dispersion is 50°C to 100°C, and the time is 2 hours to 12 hours. The above temperatures and times are merely examples and are not intended to limit the specific process parameters of this invention. Those skilled in the art can design the temperature and time in this step according to the actual solvent and dosage used, removing the solvent from the mixed dispersion through evaporation until a dry composite precursor is formed.

[0042] During the solvent removal process by evaporation, the hydroxyapatite nanowires and the oxyfluorine solid electrolyte precursor or oxyfluorine solid electrolyte powder are kept in a mixed state, so that the two are evenly distributed in the resulting composite precursor.

[0043] Step 140: Heat-treat the composite precursor to obtain the oxyfluoride solid electrolyte composite material.

[0044] Preferably, the heat treatment temperature is 600℃~900℃ and the time is 4h~12h.

[0045] After the aforementioned mixing and heat treatment, multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure, and an oxygen-fluorine solid electrolyte phase fills the network pores of the three-dimensional network structure.

[0046] During the heat treatment process, the precursor of oxygen-fluorine solid electrolyte can also be transformed into the oxygen-fluorine solid electrolyte phase.

[0047] After heat treatment, Ca-O bonds and / or hydrogen bonds are formed between the hydroxyapatite phase and the oxyfluorine solid electrolyte phase.

[0048] When using fluorinated hydroxyapatite nanowires, fluorine atoms on the surface of fluorinated hydroxyapatite form F···F interactions with fluorine atoms in the oxyfluorine solid electrolyte phase.

[0049] Method 2: Preparation of oxyfluoride solid electrolyte composite materials with a three-dimensional network-filled structure. The main method steps include: Step 210: Prepare an oxygen-fluorine solid electrolyte sol precursor solution containing lithium source, lanthanum source, niobium source and fluorine source; Specifically, lithium source, lanthanum source, niobium source and fluorine source are formulated according to the composition of the target oxygen-fluorine solid electrolyte phase, and are incorporated into the oxygen-fluorine solid electrolyte phase formed after gelation and heat treatment.

[0050] The lithium source includes one or more of lithium nitrate, lithium acetate, lithium hydroxide, lithium carbonate, or lithium alkoxides; the lanthanum source includes one or more of lanthanum nitrate, lanthanum acetate, lanthanum chloride, or lanthanum alkoxides; the niobium source includes one or more of niobium pentachloride, niobium pentaethoxy, niobium ammonium oxalate, niobium oxide, or niobic acid; and the fluorine source includes one or more of lithium fluoride, ammonium fluoride, ammonium hydrogen fluoride, trifluoroacetic acid, or metallic trifluoroacetate.

[0051] Step 220: Disperse hydroxyapatite nanowires in an oxyfluorine-based solid electrolyte sol precursor solution to obtain a mixed sol; Specifically, the chemical formula of hydroxyapatite is Ca. 10 (PO4)6(OH)2 or Ca 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2.

[0052] The amount of hydroxyapatite nanowires added is determined based on the mass percentage of hydroxyapatite phase in the obtained oxyfluoride solid electrolyte composite material being 5 wt.% to 40 wt.% and the mass percentage of oxyfluoride solid electrolyte phase being 60 wt.% to 95 wt.%.

[0053] Hydroxyapatite nanowires are dispersed in an oxyfluorine-based solid electrolyte sol precursor solution, so that the sol precursor is distributed between the hydroxyapatite nanowires and the dispersion state of the hydroxyapatite nanowires is maintained during the subsequent gelation process.

[0054] Step 230: The mixed sol is heated and gelled to obtain a composite gel containing the hydroxyapatite nanowires; Specifically, the mixed sol is heated at 60℃ to 100℃ and continuously stirred until the mixed sol transforms into a composite gel.

[0055] During the heating and gelation process, the oxyfluorine-based solid electrolyte sol precursor solution gradually forms a gel network, and hydroxyapatite nanowires are distributed in the gel network, thereby obtaining a composite gel containing oxyfluorine-based solid electrolyte precursor and hydroxyapatite nanowires.

[0056] Step 240: The composite gel is heat-treated at 500℃~800℃ to obtain an oxyfluoride solid electrolyte composite material.

[0057] Specifically, heat treatment transforms the oxyfluorine-based solid electrolyte precursor in the composite gel into an oxyfluorine-based solid electrolyte phase, which then forms between the hydroxyapatite nanowires. After gelation and heat treatment, multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure, and the oxyfluorine-based solid electrolyte phase fills the pores of this three-dimensional network structure.

[0058] Method 3: Preparation of oxyfluoride solid electrolyte composite materials with a core-shell structure. The main method steps include: Step 310: Place the oxygen-fluorine solid electrolyte particles in a fluidized bed reactor; Oxyfluorine-based solid electrolyte particles, serving as the core of a core-shell structure, remain fluidized in a fluidized bed reactor to ensure that the subsequently introduced reaction precursors can fully contact the surface of the oxyfluorine-based solid electrolyte particles.

[0059] Step 320: The reaction precursor is introduced into the fluidized bed reactor and chemical vapor deposition or atomic layer deposition is used to deposit the reaction precursor on the surface of the oxygen-fluorine solid electrolyte particles to form a hydroxyapatite shell coating the oxygen-fluorine solid electrolyte particles, thereby obtaining an oxygen-fluoride solid electrolyte composite material with a core-shell structure. The reaction precursors include: calcium source precursors, phosphorus source precursors, hydroxyl-oxygen source precursors, and precursors including or excluding fluorine source precursors.

[0060] When the introduced reaction precursor includes a calcium source precursor, a phosphorus source precursor, and a hydroxyl-oxygen source precursor, a hydroxyapatite shell is formed on the surface of the oxygen-fluorine solid electrolyte particles; when the reaction precursor also includes a fluorine source precursor, a fluorinated hydroxyapatite shell is formed on the surface of the oxygen-fluorine solid electrolyte particles. The shell thickness is 5 nm to 100 nm, and it has a structure with multiple pores penetrating the shell and / or interconnected. Hydroxyl-oxygen precursors refer to substances that provide the oxygen and hydroxyl groups required for the formation of hydroxyapatite, preferably H2O plasma.

[0061] Furthermore, after obtaining the oxyfluoride solid electrolyte composite material with a core-shell structure, the oxyfluoride solid electrolyte composite material with a hydroxyapatite shell or a fluorinated hydroxyapatite shell can be annealed to stabilize the shell structure.

[0062] The oxyfluoride solid electrolyte composite material provided in this invention comprises an oxyfluoride solid electrolyte phase and a hydroxyapatite phase. The hydroxyapatite phase accounts for 5 wt.% to 40 wt.% by mass, and the oxyfluoride solid electrolyte phase accounts for 60 wt.% to 95 wt.% by mass. By controlling the mass ratio of the two phases, a high content of the oxyfluoride solid electrolyte phase can be maintained while introducing the hydroxyapatite phase, reducing the impact of excessively high hydroxyapatite content on the continuous distribution of the oxyfluoride solid electrolyte phase. The hydroxyapatite phase and the oxyfluoride solid electrolyte phase are connected at the interface through Ca-O bonds and / or hydrogen bonds, ensuring that the two phases are not limited to physical mixing. This improves the bonding stability of the two-phase interface and reduces interfacial separation caused by insufficient bonding between the two phases during pressing, sintering, or use of the composite material.

[0063] The oxyfluoride solid electrolyte of this invention has a three-dimensional network structure or a core-shell structure. When using a three-dimensional network structure, the hydroxyapatite nanowires intertwine to form a three-dimensional network, which provides support within the composite material and disperses local stress. The oxyfluoride solid electrolyte phase fills the network pores, which helps maintain the continuous distribution of the oxyfluoride solid electrolyte phase. When using a core-shell structure, the hydroxyapatite phase coats the surface of the oxyfluoride solid electrolyte phase, improving the surface stability and interfacial bonding stability of the oxyfluoride solid electrolyte particles. Both structures can simultaneously introduce the hydroxyapatite phase while maintaining the structural stability, interfacial stability, and lithium-ion transport performance of the composite material.

[0064] Therefore, by controlling the content, morphology, spatial distribution, and interfacial structure of the oxyfluoride solid electrolyte phase and the hydroxyapatite phase, this invention can improve the structural stability and interfacial bonding stability of the oxyfluoride solid electrolyte composite material. This composite material can be used in solid electrolyte components such as solid electrolyte sheets, solid electrolyte layers, or solid electrolyte membranes, and can be applied in all-solid-state lithium batteries.

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0066] Example 1 In this embodiment, the LLNOF / HAP oxyfluoride solid electrolyte composite material with a three-dimensional network filling structure is prepared by method 1 described above, and the composite material is further made into a composite solid electrolyte sheet.

[0067] 1. Preparation of hydroxyapatite nanowires Hydroxyapatite nanowires were prepared using a hydrothermal method.

[0068] Calcium nitrate tetrahydrate Ca(NO3)2·4H2O and diammonium hydrogen phosphate (NH4)2HPO4 were dissolved separately in deionized water at a Ca / P molar ratio of 1.67, then mixed, and urea was added as a pH adjuster to adjust the pH of the resulting mixed solution to 10±0.5.

[0069] The mixed solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 180°C for 24 hours. After the reaction was completed and the mixture was allowed to cool naturally, the reaction product was centrifuged, washed, and dried sequentially to obtain hydroxyapatite nanowires.

[0070] Characterization revealed that the obtained hydroxyapatite nanowires had a diameter of approximately 80 nm and a length of approximately 5 μm.

[0071] 2. Preparation of LLNOF precursors LLNOF precursors were prepared using the sol-gel method.

[0072] Lithium acetate, lanthanum nitrate, niobium oxalate, and lithium fluoride were weighed according to the molar ratio of Li, La, Nb, and F of 1.25:0.58:2:1, and the above raw materials were added to anhydrous ethanol to form a mixture.

[0073] Citric acid was added as a complexing agent to the resulting mixture. Citric acid reacted with metal ions Li. + La 3+ and Nb 5+ The total molar ratio is 2:1. The resulting mixture is placed in a 70°C water bath and stirred to form a sol.

[0074] The obtained sol was first dried at 80℃ for 12 h, and then dried at 120℃ for 12 h to obtain LLNOF precursor dry gel.

[0075] 3. Preparation of LLNOF / HAP oxyfluoride solid electrolyte composite material The ingredients were prepared according to the following formula: the mass percentage of hydroxyapatite phase in the obtained oxyfluoride solid electrolyte composite material was 20 wt.% and the mass percentage of oxyfluoride solid electrolyte phase was 80 wt.%.

[0076] The hydroxyapatite nanowires obtained in step 1 were added to anhydrous ethanol and subjected to ultrasonic treatment for 30 minutes to disperse the hydroxyapatite nanowires in the anhydrous ethanol.

[0077] The LLNOF precursor dry gel prepared in step 2 was added to the hydroxyapatite nanowire dispersion, and the mixture was stirred for 4 hours to distribute the LLNOF precursor between the hydroxyapatite nanowires, thus obtaining a mixed dispersion.

[0078] Part of the anhydrous ethanol in the mixed dispersion was removed by evaporation, and then dried under vacuum at 80°C for 12 h to remove the remaining solvent, yielding a dried composite precursor.

[0079] The composite precursor was placed in a nitrogen atmosphere and heated to 750℃ at a heating rate of 5℃ / min, and held at 750℃ for 8 hours. After heat treatment, it was allowed to cool naturally to obtain LLNOF / HAP oxyfluoride solid electrolyte composite powder.

[0080] After the aforementioned dispersion, mixing, drying, and heat treatment, multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure, and the LLNOF oxyfluorine solid electrolyte phase fills the network pores of the three-dimensional network structure.

[0081] 4. Preparation of composite solid electrolyte sheets The LLNOF / HAP oxyfluoride solid electrolyte composite powder obtained in step 3 was pressed into a composite solid electrolyte blank with a diameter of 12 mm and a thickness of about 1 mm under a pressure of 500 MPa.

[0082] The composite solid electrolyte preform was heated to 750℃ at a heating rate of 2℃ / min and then sintered at 750℃ for 4 hours to obtain a dense LLNOF / HAP composite solid electrolyte sheet.

[0083] 5. Ionic conductivity test The ionic conductivity of the obtained composite solid electrolyte sheet was tested using the AC impedance method. The test frequency range was 1Hz to 10MHz, the AC signal amplitude was 10mV, and the test temperature was 25℃.

[0084] Test results show that the ionic conductivity of the composite solid electrolyte sheet obtained in this embodiment is 1.2 × 10⁻⁶. -3 S / cm. Under the same test conditions, the ionic conductivity of pure LLNOF solid electrolyte sheet is 1.5 × 10⁻⁶. -3 S / cm. This shows that even after introducing 20 wt.% hydroxyapatite phase, the composite solid electrolyte still maintains 10. -3 The ionic conductivity, on the order of S / cm, did not show a significant decrease.

[0085] 6. Mechanical performance testing The bending strength of the obtained composite solid electrolyte sheet was tested using the three-point bending method.

[0086] Test results show that the flexural strength of the composite solid electrolyte sheet obtained in this embodiment is 85 MPa, while the flexural strength of the pure LLNOF solid electrolyte sheet is 42 MPa. The flexural strength of the composite solid electrolyte sheet obtained in this embodiment is approximately 102% higher than that of the pure LLNOF solid electrolyte sheet.

[0087] 7. Assembly and electrochemical performance testing of all-solid-state batteries An all-solid-state battery was assembled using the LLNOF / HAP composite solid-state electrolyte sheet prepared in this embodiment. The all-solid-state battery includes a positive electrode, a composite solid-state electrolyte sheet, and a negative electrode. The positive electrode uses NCM811 positive electrode material coated with LiNbO3, and the negative electrode uses lithium metal.

[0088] The obtained all-solid-state battery was subjected to charge-discharge tests within a voltage range of 2.8V to 4.3V at a 0.1C rate.

[0089] The results of the first charge and discharge test are as follows Figure 2 The results show that the initial charge specific capacity of the obtained all-solid-state battery is 198 mAh / g, the initial discharge specific capacity is 179 mAh / g, and the initial coulombic efficiency is 90.4%. Under the same conditions, the initial coulombic efficiency of the all-solid-state battery assembled using pure LLNOF solid electrolyte sheets is 84.2%, and the initial coulombic efficiency of this embodiment is improved by 6.2 percentage points.

[0090] Cyclic performance test results show that the capacity retention rate of the obtained all-solid-state battery is 92% after 100 cycles and 85% after 200 cycles.

[0091] 8. Interface Characterization X-ray photoelectron spectroscopy analysis was performed on the surface of the cycled lithium metal anode, and the results are as follows: Figure 1 As shown. Test results indicate that LiF and CaF2 signals were detected on the surface of the lithium metal anode after cycling, and the LiF content in the interface layer was increased by about 40% compared with the battery system using a pure LLNOF solid electrolyte sheet. This shows that the LLNOF / HAP composite solid electrolyte sheet of this embodiment can promote the formation of a LiF-containing solid electrolyte interface layer.

[0092] Example 2 In this embodiment, fluorinated hydroxyapatite nanowires were used to prepare an LLNOF / F-HAP oxyfluoride solid electrolyte composite material with a three-dimensional network-filled structure using the method described above (Method 1).

[0093] 1. Preparation of fluorinated hydroxyapatite nanowires Fluorohydroxyapatite nanowires were prepared by a hydrothermal method.

[0094] Calcium nitrate tetrahydrate Ca(NO3)2·4H2O and diammonium hydrogen phosphate (NH4)2HPO4 were dissolved separately in deionized water with a Ca / P molar ratio of 1.67. After mixing, sodium fluoride was added as a fluoride source, and the F / Ca molar ratio was adjusted to 0.15.

[0095] The fluorohydroxyapatite prepared in this embodiment has the chemical formula Ca. 10 (PO4)6(OH) 0.5 F 1.5 Of which, 75% of the hydroxyl groups are fluorinated.

[0096] Urea was added to the resulting mixture as a pH adjuster to adjust the pH of the mixture to 10 ± 0.5. The mixture was then transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 180°C for 24 hours.

[0097] After the reaction was completed and the product was allowed to cool naturally, the product was centrifuged and washed three times each with deionized water and anhydrous ethanol, and then dried to obtain fluorohydroxyapatite nanowires.

[0098] Characterization revealed that the obtained fluorinated hydroxyapatite nanowires had a diameter of approximately 80 nm and a length of approximately 5 μm, and their morphology was basically consistent with that of the hydroxyapatite nanowires prepared in Example 1.

[0099] 2. Preparation of LLNOF precursors LLNOF precursors were prepared using the sol-gel method.

[0100] Lithium acetate, lanthanum nitrate, niobium oxalate, and lithium fluoride were weighed according to the molar ratio of Li, La, Nb, and F of 1.25:0.58:2:1, and the above raw materials were added to anhydrous ethanol.

[0101] Citric acid was added as a complexing agent to the resulting mixture. Citric acid reacted with metal ions Li. + La 3+ and Nb 5+ The total molar ratio is 2:1. The mixture is placed in a 70°C water bath and stirred to form a sol.

[0102] The obtained sol was first dried at 80℃ for 12 h, and then dried at 120℃ for 12 h to obtain LLNOF precursor dry gel.

[0103] 3. Preparation of LLNOF / F-HAP oxyfluoride solid electrolyte composite material The ingredients were prepared according to the following formula: the mass percentage of fluorinated hydroxyapatite phase in the obtained oxyfluoride solid electrolyte composite material was 20 wt.% and the mass percentage of oxyfluoride solid electrolyte phase was 80 wt.%.

[0104] The fluorohydroxyapatite nanowires obtained in step 1 were added to anhydrous ethanol and subjected to ultrasonic treatment for 30 minutes to disperse the fluorohydroxyapatite nanowires in anhydrous ethanol.

[0105] The LLNOF precursor dry gel prepared in step 2 was added to the obtained fluorohydroxyapatite nanowire dispersion, and the mixture was stirred for 4 hours to distribute the LLNOF precursor between the fluorohydroxyapatite nanowires, thus obtaining a mixed dispersion.

[0106] Part of the anhydrous ethanol in the mixed dispersion was removed by evaporation, and then dried under vacuum at 80°C for 12 h to remove the remaining solvent, yielding a dried composite precursor.

[0107] The composite precursor was placed in a nitrogen atmosphere and heated to 750℃ at a heating rate of 5℃ / min, and held at 750℃ for 8 hours. After heat treatment, it was allowed to cool naturally to obtain LLNOF / F-HAP oxyfluoride solid electrolyte composite powder.

[0108] After the aforementioned dispersion, mixing, drying, and heat treatment, multiple fluorinated hydroxyapatite nanowires intertwine to form a three-dimensional network structure, with the LLNOF oxyfluorine-based solid electrolyte phase filling the network pores. An interfacial bond is formed between the fluorinated hydroxyapatite phase and the LLNOF oxyfluorine-based solid electrolyte phase.

[0109] 4. Preparation of composite solid electrolyte sheets The LLNOF / F-HAP oxyfluoride solid electrolyte composite powder obtained in step 3 was pressed into a composite solid electrolyte blank with a diameter of 12 mm and a thickness of about 1 mm under a pressure of 500 MPa.

[0110] The composite solid electrolyte preform was heated to 750℃ at a heating rate of 2℃ / min and then sintered at 750℃ for 4 hours to obtain a dense LLNOF / F-HAP composite solid electrolyte sheet.

[0111] 5. Ionic conductivity test The ionic conductivity of the composite solid electrolyte sheet prepared in this embodiment was tested according to the AC impedance test conditions described in Example 1.

[0112] Test results show that the ionic conductivity of the LLNOF / F-HAP composite solid electrolyte sheet obtained in this embodiment is 1.5 × 10⁻⁶ at 25 °C. -3 Its S / cm is comparable to the ionic conductivity of pure LLNOF solid electrolyte sheets.

[0113] Compared with the composite solid electrolyte sheet prepared by unfluorinated hydroxyapatite nanowires in Example 1, this example further reduces the influence of the introduction of hydroxyapatite on the ionic conductivity of the composite solid electrolyte while maintaining high mechanical strength.

[0114] 6. Mechanical performance testing The composite solid electrolyte sheet prepared in this embodiment was subjected to bending strength test according to the three-point bending test method described in Example 1.

[0115] Test results show that the flexural strength of the LLNOF / F-HAP composite solid electrolyte sheet obtained in this embodiment is 78 MPa. Compared with the flexural strength of the pure LLNOF solid electrolyte sheet (42 MPa), the flexural strength of the composite solid electrolyte sheet obtained in this embodiment is increased by approximately 85.7%.

[0116] 7. Assembly and electrochemical performance testing of all-solid-state batteries An all-solid-state battery was assembled using the LLNOF / F-HAP composite solid-state electrolyte sheet prepared in this embodiment. The positive electrode, negative electrode, assembly method, and testing conditions of the all-solid-state battery were the same as in Example 1.

[0117] The obtained all-solid-state battery was subjected to charge-discharge tests within a voltage range of 2.8V to 4.3V at a 0.1C rate.

[0118] The results of the first charge and discharge test are as follows Figure 2 This indicates that the first charge specific capacity of the obtained all-solid-state battery is 201 mAh / g, the first discharge specific capacity is 185 mAh / g, and the first coulombic efficiency is 92.1%.

[0119] Cyclic performance test results show that the capacity retention rate of the obtained all-solid-state battery is 93.2% after 100 cycles and 87.5% after 200 cycles.

[0120] Compared with Example 1, the all-solid-state battery obtained in this example has higher initial coulombic efficiency and cycle capacity retention.

[0121] 8. Interface Characterization X-ray photoelectron spectroscopy analysis was performed on the surface of the cycled lithium metal anode, and the results are as follows: Figure 1 As shown.

[0122] Test results show that obvious LiF and CaF2 signals were detected on the surface of the lithium metal anode after cycling. Compared with the battery system using pure LLNOF solid electrolyte sheet, the relative LiF content in the interface layer obtained in this embodiment is increased by about 65%; while the relative LiF content in the interface layer obtained in Example 1 is increased by about 40%. Therefore, compared with the use of hydroxyapatite in Example 1, the use of fluorinated hydroxyapatite can further promote the formation of the LiF-containing interface layer after cycling.

[0123] The CaF2 signal intensity on the lithium metal anode surface after cycling in this embodiment is about 1.5 times that in Example 1, indicating that the interface layer formed by cycling has a higher CaF2 content after using fluorinated hydroxyapatite.

[0124] Peak segmentation analysis of the F 1s spectrum revealed characteristic peaks at binding energies of approximately 684.5 eV and 688.2 eV, belonging to LiF and metal-fluorine bonds, respectively. In this embodiment, the area of ​​the characteristic peak at approximately 688.2 eV accounts for approximately 25% of the total peak area of ​​the F 1s spectrum, while the corresponding proportion in Example 1 was approximately 12%.

[0125] The above results indicate that the introduction of fluorinated hydroxyapatite alters the composition of fluorine-containing species at the electrode-solid electrolyte interface after cycling, resulting in a higher content of LiF, CaF2, and other metal-fluorine bonded species in the interface layer, which is beneficial for improving the stability of the interface layer. This change in interface composition corresponds to the higher initial coulombic efficiency and cycle capacity retention of the all-solid-state battery obtained in this embodiment.

[0126] Example 3 In this embodiment, method 2 is used to prepare an LLNOF / HAP oxyfluoride solid electrolyte composite material with a three-dimensional network filling structure, and the composite material is further made into a composite solid electrolyte sheet.

[0127] 1. Preparation of hydroxyapatite nanowires Hydroxyapatite nanowires were prepared using a hydrothermal method.

[0128] Calcium nitrate tetrahydrate Ca(NO3)2·4H2O and diammonium hydrogen phosphate (NH4)2HPO4 were dissolved separately in deionized water at a Ca / P molar ratio of 1.67. After mixing, urea was added as a pH adjuster to adjust the pH of the resulting mixed solution to 10±0.5.

[0129] The mixed solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 180°C for 24 hours. After the reaction was completed and the mixture was allowed to cool naturally, the reaction product was centrifuged, washed, and dried sequentially to obtain hydroxyapatite nanowires.

[0130] Characterization revealed that the obtained hydroxyapatite nanowires had a diameter of approximately 80 nm and a length of approximately 5 μm.

[0131] 2. Preparation of LLNOF sol precursor solution Lithium acetate, lanthanum nitrate, niobium oxalate, and lithium fluoride were weighed according to the molar ratio of Li, La, Nb, and F of 1.25:0.58:2:1, and the above raw materials were added to anhydrous ethanol.

[0132] Citric acid was added as a complexing agent to the resulting mixture. Citric acid reacted with metal ions Li. + La 3+ and Nb 5+ The ratio of their total molar amounts is 2:1.

[0133] The mixture was placed in a 70°C water bath and stirred to disperse or dissolve lithium acetate, lanthanum nitrate, niobium oxalate and lithium fluoride in anhydrous ethanol, and then complexed with citric acid to form an LLNOF sol precursor solution.

[0134] 3. Preparation of LLNOF / HAP composite gel The final oxyfluoride solid electrolyte composite material was prepared by mixing 20 wt.% of hydroxyapatite phase and 80 wt.% of oxyfluoride solid electrolyte phase.

[0135] The hydroxyapatite nanowires obtained in step 1 are added to the LLNOF sol precursor solution obtained in step 2, and the mixture is stirred continuously to disperse the hydroxyapatite nanowires in the LLNOF sol precursor solution, thereby obtaining a mixed sol.

[0136] The mixed sol was heated to 80°C and stirred continuously to allow the solvent in the mixed sol to gradually evaporate and gel until a composite gel containing hydroxyapatite nanowires and LLNOF precursor was formed.

[0137] During the gelation process, the LLNOF sol precursor is distributed between the hydroxyapatite nanowires and is fixed around the hydroxyapatite nanowires as the gel network is formed.

[0138] The obtained composite gel was dried at 120°C for 12 hours to remove residual solvent, resulting in a dried composite gel.

[0139] 4. Preparation of LLNOF / HAP oxyfluoride solid electrolyte composite material The dried composite gel obtained in step 3 was placed in a nitrogen atmosphere and heated to 750°C at a heating rate of 5°C / min, and kept at 750°C for 8 hours.

[0140] During heat treatment, the LLNOF precursor in the composite gel is transformed into the LLNOF oxyfluoride solid electrolyte phase. After heat treatment, the mixture is allowed to cool naturally to obtain the LLNOF / HAP oxyfluoride solid electrolyte composite powder.

[0141] After the aforementioned dispersion, gelation, and heat treatment, multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure, and an LLNOF oxyfluorine-based solid electrolyte phase is formed and fills the network pores of the three-dimensional network structure.

[0142] 5. Preparation of composite solid electrolyte sheets The LLNOF / HAP oxyfluoride solid electrolyte composite powder obtained in step 4 was pressed into a composite solid electrolyte blank with a diameter of 12 mm and a thickness of about 1 mm under a pressure of 500 MPa.

[0143] The composite solid electrolyte preform was heated to 750°C at a heating rate of 2°C / min and then sintered at 750°C for 4 hours to obtain a dense LLNOF / HAP composite solid electrolyte sheet.

[0144] 6. Ionic conductivity test The ionic conductivity of the composite solid electrolyte sheet prepared in this embodiment was tested according to the AC impedance test conditions described in Example 1.

[0145] Test results show that the ionic conductivity of the LLNOF / HAP composite solid electrolyte sheet obtained in this embodiment is 1.4 × 10⁻⁶ at 25 °C. - ³ S / cm, which is comparable to the ionic conductivity of pure LLNOF solid electrolyte sheet, and slightly lower than the conductivity of the fluorinated hydroxyapatite composite system in Example 2.

[0146] 7. Mechanical performance testing The composite solid electrolyte sheet prepared in this embodiment was subjected to bending strength test according to the three-point bending test method described in Example 1.

[0147] Test results show that the flexural strength of the LLNOF / HAP composite solid electrolyte sheet obtained in this embodiment is 75 MPa. Compared with the flexural strength of the pure LLNOF solid electrolyte sheet (42 MPa), the flexural strength of the composite solid electrolyte sheet obtained in this embodiment is increased by approximately 78.6%, demonstrating excellent mechanical reinforcement.

[0148] 8. Assembly and electrochemical performance testing of all-solid-state batteries An all-solid-state battery was assembled using the LLNOF / HAP composite solid-state electrolyte sheet prepared in this embodiment. The positive electrode, negative electrode, assembly method, and testing conditions of the all-solid-state battery were the same as in Example 1.

[0149] The obtained all-solid-state battery was subjected to charge-discharge tests within a voltage range of 2.8V to 4.3V at a 0.1C rate.

[0150] The results of the first charge and discharge test are as follows Figure 2 This indicates that the first charge specific capacity of the obtained all-solid-state battery is 198 mAh / g, the first discharge specific capacity is 178 mAh / g, and the first coulombic efficiency is 89.9%.

[0151] Cyclic performance test results show that the capacity retention rate of the obtained all-solid-state battery is 92.1% after 100 cycles and 85.2% after 200 cycles.

[0152] 9. Interface Characterization X-ray photoelectron spectroscopy analysis was performed on the surface of the cycled lithium metal anode, and the results are as follows: Figure 1 As shown.

[0153] Test results show that obvious LiF and CaF2 signals were detected on the surface of the lithium metal anode after cycling. Compared with the battery system using pure LLNOF solid electrolyte sheet, the relative LiF content in the interface layer obtained in this embodiment is increased by about 42%. Compared with the fluorinated hydroxyapatite system in Example 2 (relative LiF content increased by about 65%), the amount of LiF generated in the interface layer of this embodiment is less, but it is still significantly better than the pure LLNOF system.

[0154] Peak segmentation analysis of the F 1s spectrum revealed characteristic peaks at binding energies of approximately 684.5 eV and 688.2 eV, belonging to LiF and metal-fluorine bonds, respectively. In this embodiment, the area of ​​the characteristic peak at approximately 688.2 eV accounts for approximately 14% of the total peak area of ​​the F 1s spectrum, while the corresponding proportion is approximately 12% in Example 1 and approximately 25% in Example 2.

[0155] The above results indicate that in-situ synthesis of the LLNOF / HAP oxyfluoride solid electrolyte composite material with a three-dimensional network-filled structure via sol-gel is more conducive to the formation of a stable interface layer rich in LiF and metal-fluorine bond species after cycling than wet mixing, but its promoting effect is weaker than that of fluorinated hydroxyapatite. This interface composition characteristic is consistent with the electrochemical performance of the all-solid-state battery obtained in this example, which exhibits higher initial coulombic efficiency and cycle capacity retention than the pure LLNOF system, but lower than the fluorinated hydroxyapatite system of Example 2.

[0156] Example 4 In this embodiment, the atomic layer deposition method in method 3 is used to form a fluorinated hydroxyapatite shell on the surface of LLNOF particles to prepare an LLNOF / F-HAP oxyfluoride solid electrolyte composite material with a core-shell structure, and the composite material is further made into a composite solid electrolyte sheet.

[0157] 1. Preparation of LLNOF core particles LLNOF core particles were prepared using the sol-gel method.

[0158] Lithium acetate, lanthanum nitrate, niobium oxalate, and lithium fluoride were weighed according to the molar ratio of Li, La, Nb, and F of 1.25:0.58:2:1, and the above raw materials were added to anhydrous ethanol.

[0159] Citric acid was added as a complexing agent to the resulting mixture. Citric acid reacts with metal ions Li. + La 3+ and Nb 5+ The total molar ratio is 2:1. The resulting mixture is placed in a 70°C water bath and stirred to mix the raw materials and form a sol.

[0160] The obtained sol was first dried at 80℃ for 12 h, and then dried at 120℃ for 12 h to obtain LLNOF precursor dry gel.

[0161] The LLNOF precursor dry gel was placed in a nitrogen atmosphere and heated to 750°C at a heating rate of 5°C / min, and held at 750°C for 8 hours. After heat treatment, it was allowed to cool naturally to obtain LLNOF powder.

[0162] The obtained LLNOF powder was ground and then passed through a 200-mesh sieve to obtain LLNOF core particles with an average particle size of approximately 500 nm.

[0163] 2. Deposition of fluorinated hydroxyapatite crust A fluorohydroxyapatite shell was deposited on the surface of the LLNOF core particles prepared in step 1 using atomic layer deposition. The fluorohydroxyapatite shell accounted for approximately 7 wt.% of the total mass of the composite material.

[0164] LLNOF core particles were placed in the atomic layer deposition reaction chamber and kept in a fluidized state in fluidized bed mode. The atomic layer deposition temperature was set to 250°C.

[0165] Bis(2,2,6,6-tetramethyl-3,5-heptadecyl)calcium (Ca(thd)2) was used as the calcium source precursor, trimethyl phosphate as the phosphorus source precursor, titanium tetrafluoride (TiF4) as the fluorine source precursor, and H2O plasma as the oxygen and hydroxyl sources.

[0166] Each atomic layer deposition cycle includes, in sequence: Ca(thd)2 precursor pulsed for 0.5s, followed by 20s purging; Trimethyl phosphate precursor was pulsed for 0.5 s, followed by 20 s purge; TiF4 precursor pulse for 0.3 s, followed by 20 s purge; H2O plasma pulse for 2 seconds, followed by purging for 30 seconds.

[0167] Perform 200 atomic layer deposition cycles according to the above pulse sequence, so that calcium source precursor, phosphorus source precursor, fluorine source precursor, as well as oxygen source and hydroxyl source are alternately adsorbed on the surface of LLNOF core particles and undergo surface reaction to form a fluorinated hydroxyapatite shell coating LLNOF core particles.

[0168] The thickness of the deposited shell is approximately 15 nm.

[0169] After deposition, the LLNOF particles with the fluorinated hydroxyapatite shell were placed in a nitrogen atmosphere and annealed at 400°C for 30 min to stabilize the shell structure, thus obtaining LLNOF / F-HAP oxyfluoride solid electrolyte composite powder with a core-shell structure.

[0170] Transmission electron microscopy revealed that the obtained composite powder possesses a core-shell structure, with LLNOF forming the core and fluorinated hydroxyapatite forming the shell encapsulating the core. The shell exhibits a structure where amorphous and nanocrystalline phases coexist, and contains multiple pores with a porosity of approximately 35%.

[0171] 3. Preparation of composite solid electrolyte sheets The LLNOF / F-HAP oxyfluoride solid electrolyte composite powder with a core-shell structure obtained in step 2 was pressed into a composite solid electrolyte blank with a diameter of 12 mm and a thickness of about 1 mm under a pressure of 500 MPa.

[0172] The composite solid electrolyte preform was heated to 700℃ at a heating rate of 2℃ / min and then sintered at 700℃ for 2 hours to obtain a dense LLNOF / F-HAP composite solid electrolyte sheet.

[0173] The secondary sintering temperature and holding time used in this embodiment are lower than those in Examples 1, 2, and 3, in order to reduce excessive diffusion or changes in the shell structure between the fluorohydroxyapatite shell and the LLNOF core during the secondary sintering process.

[0174] 4. Ionic conductivity test The ionic conductivity of the composite solid electrolyte sheet prepared in this embodiment was tested according to the AC impedance test conditions of Example 1.

[0175] Test results show that the composite solid electrolyte sheet obtained in this embodiment has an ionic conductivity of 1.7 × 10⁻⁶ at 25 °C. -3 S / cm, higher than 1.5×10⁻⁶ for pure LLNOF solid electrolyte sheets.-3 S / cm.

[0176] The above results indicate that forming a porous fluorohydroxyapatite shell with a thickness of approximately 15 nm on the surface of LLNOF particles did not reduce the ionic conductivity of the composite solid electrolyte. The pores in the porous shell provide a transport path for lithium ions to pass through the shell, and the interface formed between the LLNOF core and the fluorohydroxyapatite shell also facilitates ion transport in the composite material.

[0177] 5. Mechanical performance testing The composite solid electrolyte sheet prepared in this embodiment was subjected to bending strength test according to the three-point bending test method described in Example 1.

[0178] Test results show that the flexural strength of the composite solid electrolyte sheet obtained in this embodiment is 68 MPa, while the flexural strength of the pure LLNOF solid electrolyte sheet is 42 MPa. The flexural strength of the composite solid electrolyte sheet obtained in this embodiment is approximately 61.9% higher than that of the pure LLNOF solid electrolyte sheet.

[0179] The flexural strength of this embodiment is lower than that of Embodiments 1, 2, and 3, but still significantly higher than that of pure LLNOF solid electrolyte sheets. This is because the fluorinated hydroxyapatite in this embodiment is mainly distributed on the surface of LLNOF particles and does not form a three-dimensional nanowire network structure that penetrates the interior of the composite material.

[0180] 6. Assembly and electrochemical performance testing of all-solid-state batteries An all-solid-state battery was assembled using the LLNOF / F-HAP composite solid-state electrolyte sheet prepared in this embodiment. The positive electrode, negative electrode, assembly method, and testing conditions of the all-solid-state battery were the same as in Example 1.

[0181] The obtained all-solid-state battery was subjected to charge-discharge tests at a rate of 0.1C and a voltage range of 2.8V to 4.3V.

[0182] The results of the first charge and discharge test are as follows Figure 2 This indicates that the first charge specific capacity of the obtained all-solid-state battery is 202 mAh / g, the first discharge specific capacity is 185 mAh / g, and the first coulombic efficiency is 91.5%.

[0183] Under the same conditions, the initial coulombic efficiency of the all-solid-state battery assembled using pure LLNOF solid electrolyte sheets is 84.2%. Therefore, the initial coulombic efficiency of the all-solid-state battery obtained in this embodiment is improved by 7.3 percentage points.

[0184] Cyclic performance test results show that the capacity retention rate of the obtained all-solid-state battery is 94% after 100 cycles and 88% after 200 cycles.

[0185] 7. Interface Characterization X-ray photoelectron spectroscopy analysis was performed on the surface of the cycled lithium metal anode, and the results are as follows: Figure 1 As shown.

[0186] Test results show that LiF, CaF2 and a small amount of LaF3 signals were detected on the surface of the lithium metal anode after cycling.

[0187] Compared to battery systems using pure LLNOF solid electrolyte sheets, the relative LiF content in the interface layer obtained in this embodiment is increased by approximately 55%. This increase is higher than approximately 40% in Example 1 and 42% in Example 3, but lower than approximately 65% ​​in Example 2.

[0188] Peak segmentation analysis of the F 1s spectrum revealed characteristic peaks at binding energies of approximately 684.5 eV and 688.2 eV, belonging to LiF and metal-fluorine bonds, respectively. In this example, the area of ​​the characteristic peak at approximately 688.2 eV accounts for approximately 18% of the total peak area of ​​the F 1s spectrum; the corresponding proportions in Examples 1, 2, and 3 are approximately 12%, 25%, and 14%, respectively.

[0189] The above results indicate that after forming a fluorinated hydroxyapatite shell using atomic layer deposition, the cyclically formed interface layer has a high content of LiF and metal-fluorine bond species, and its fluorine species composition is different from that of Examples 1, 2, and 3.

[0190] via Ar + Sputter depth profiling was used to analyze the interface layer, estimating its thickness to be approximately 30 nm to 40 nm. The interface layer was relatively uniformly distributed along the contact area between the electrode and the solid electrolyte.

[0191] Transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) was performed on the electrode-solid electrolyte interface after cycling. The results showed a gradient distribution of fluorine (F) in the direction extending from the solid electrolyte side to the lithium metal anode side, indicating that the fluorine-containing shell in the core-shell structure participated in the formation of the interface layer during cycling.

[0192] 8. Analysis In this embodiment, fluorinated hydroxyapatite is concentrated on the surface of LLNOF particles using atomic layer deposition. Even with the fluorinated hydroxyapatite shell accounting for approximately 7 wt.% of the total mass of the composite material, the resulting composite solid electrolyte sheet still exhibits a density of 1.7 × 10⁻⁶. -3 It has an ionic conductivity of S / cm and a flexural strength of 68MPa.

[0193] Compared with Examples 1, 2, and 3, the flexural strength of this example is relatively low, but its ionic conductivity, initial coulombic efficiency, and cycle capacity retention are high. These results indicate that by controlling the distribution of the fluorohydroxyapatite phase on the surface of LLNOF particles, as well as the thickness and pore structure of the shell, the amount of fluorohydroxyapatite used can be reduced while maintaining the ion transport performance, mechanical properties, and interfacial stability of the composite solid electrolyte.

[0194] Comparative Example 1 This comparative example prepared a pure LLNOF solid electrolyte without hydroxyapatite phase, and further prepared it into a pure LLNOF solid electrolyte sheet for comparison with the oxyfluoride solid electrolyte composite materials prepared in Examples 1, 2, 3, and 4.

[0195] 1. Preparation of LLNOF precursors LLNOF precursors were prepared using the sol-gel method.

[0196] Lithium acetate, lanthanum nitrate, niobium oxalate, and lithium fluoride were weighed according to the molar ratio of Li, La, Nb, and F of 1.25:0.58:2:1, and the above raw materials were added to anhydrous ethanol.

[0197] Citric acid was added as a complexing agent to the resulting mixture. Citric acid reacts with metal ions Li. + La 3+ and Nb 5+ The total molar ratio is 2:1. The mixture is placed in a 70°C water bath and stirred to mix the raw materials and form a sol.

[0198] The obtained sol was first dried at 80℃ for 12 h, and then dried at 120℃ for 12 h to obtain LLNOF precursor dry gel.

[0199] 2. Preparation of LLNOF solid electrolyte powder The obtained LLNOF precursor dry gel was placed in a nitrogen atmosphere and heated to 750℃ at a heating rate of 5℃ / min, and held at 750℃ for 8 hours.

[0200] After heat treatment, the mixture is allowed to cool naturally to obtain pure LLNOF solid electrolyte powder.

[0201] 3. Preparation of pure LLNOF solid electrolyte sheets The obtained pure LLNOF solid electrolyte powder was pressed into a solid electrolyte blank with a diameter of 12 mm and a thickness of about 1 mm under a pressure of 500 MPa.

[0202] The solid electrolyte preform was heated to 750°C at a heating rate of 2°C / min and then sintered at 750°C for 4 hours to obtain a dense pure LLNOF solid electrolyte sheet.

[0203] 4. Ionic conductivity test The ionic conductivity of the pure LLNOF solid electrolyte sheet was tested using the AC impedance method. The test frequency range was 1Hz to 10MHz, the AC signal amplitude was 10mV, and the test temperature was 25℃.

[0204] Test results show that the ionic conductivity of the pure LLNOF solid electrolyte sheet obtained in this comparative example is 1.5 × 10⁻⁶. -3 S / cm.

[0205] 5. Mechanical performance testing The bending strength of the obtained pure LLNOF solid electrolyte sheet was tested using the three-point bending method.

[0206] Test results show that the flexural strength of the pure LLNOF solid electrolyte sheet obtained in this comparative example is 42 MPa.

[0207] 6. Assembly and electrochemical performance testing of all-solid-state batteries All-solid-state batteries were assembled using the pure LLNOF solid electrolyte sheet prepared in this comparative example.

[0208] The all-solid-state battery includes a positive electrode, a pure LLNOF solid electrolyte sheet, and a negative electrode. The positive electrode uses NCM811 positive electrode material coated with LiNbO3, and the negative electrode uses lithium metal.

[0209] The obtained all-solid-state battery was subjected to charge-discharge tests at a rate of 0.1C and a voltage range of 2.8V to 4.3V.

[0210] The results of the first charge and discharge test are as follows Figure 2 This indicates that the first charge specific capacity of the obtained all-solid-state battery is 196 mAh / g, the first discharge specific capacity is 165 mAh / g, and the first coulombic efficiency is 84.2%.

[0211] Cyclic performance test results show that the capacity retention rate of the obtained all-solid-state battery is 78% after 100 cycles and 62% after 200 cycles.

[0212] 7. Comparative Analysis Compared with the comparative example, the capacity retention rates of the all-solid-state battery obtained in Example 1 after 100 and 200 cycles were 92% and 85%, respectively; the capacity retention rates of the all-solid-state battery obtained in Example 2 after 100 and 200 cycles were 93.2% and 87.5%, respectively; the capacity retention rates of the all-solid-state battery obtained in Example 3 after 100 and 200 cycles were 92.1% and 85.2%, respectively; and the capacity retention rates of the all-solid-state battery obtained in Example 4 after 100 and 200 cycles were 94% and 88%, respectively, all of which are higher than the pure LLNOF solid electrolyte sheet obtained in the comparative example.

[0213] Meanwhile, the flexural strength of the composite solid electrolyte sheets obtained in Examples 1, 2, 3, and 4 is higher than that of the pure LLNOF solid electrolyte sheet obtained in this comparative example.

[0214] The above results indicate that, under the same LLNOF composition and preparation conditions, the introduction of hydroxyapatite or fluorinated hydroxyapatite phase can improve the flexural strength of the solid electrolyte sheet and is beneficial to improving the initial coulombic efficiency and cycle capacity retention of all-solid-state batteries assembled using the solid electrolyte sheet.

[0215] Comparative Example 2 This comparative example uses irregularly shaped hydroxyapatite to composite with LLNOF, preparing an LLNOF / HAP solid electrolyte composite material without a three-dimensional network structure of hydroxyapatite nanowires, to be compared with the oxyfluoride solid electrolyte composite material in Example 1 that uses hydroxyapatite nanowires to form a three-dimensional network structure.

[0216] Except for replacing the hydroxyapatite nanowires in Example 1 with irregularly shaped hydroxyapatite particles, the composition of the LLNOF precursor, the mass ratio of the hydroxyapatite phase to the oxyfluorine solid electrolyte phase, and the mixing, heat treatment, and sheeting conditions in this comparative example are all the same as in Example 1. Therefore, except for the preparation of hydroxyapatite particles, the rest of the preparation process will not be described in detail.

[0217] 1. Preparation of hydroxyapatite particles Hydroxyapatite particles were prepared by co-precipitation method.

[0218] Calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) and diammonium hydrogen phosphate (NH4)2HPO4 were dissolved separately in deionized water at a Ca / P molar ratio of 1.67. The resulting solutions were then mixed, and the pH of the mixture was adjusted to 10 ± 0.5 using ammonia.

[0219] The mixed solution was placed in an 80°C water bath and stirred for 2 hours. After the reaction was completed, the resulting reaction solution was allowed to stand and age for 12 hours.

[0220] After aging, the resulting reaction product was centrifuged and washed three times each with deionized water and anhydrous ethanol. The washed reaction product was dried at 100°C for 12 hours and then calcined at 600°C for 2 hours to obtain hydroxyapatite particles.

[0221] Characterized by scanning electron microscopy and transmission electron microscopy, the obtained hydroxyapatite was found to be irregularly shaped particles with a particle size of 200 nm to 500 nm, and no nanowire morphology was observed.

[0222] Examples 2-4 are the same as in Example 1, resulting in a dense composite solid electrolyte sheet.

[0223] 5. Ionic conductivity test The ionic conductivity of the composite solid electrolyte sheet prepared in this comparative example was tested according to the AC impedance test conditions described in Example 1.

[0224] Test results show that the composite solid electrolyte sheet obtained in this comparative example has an ionic conductivity of 8.5 × 10⁻⁶ at 25 °C. -4 S / cm, lower than 1.5 × 10⁻⁶ for pure LLNOF solid electrolyte sheets. -3 The S / cm ratio is also lower than the 1.2 × 10⁻⁶ of the composite solid electrolyte sheet obtained in Example 1. -3 S / cm.

[0225] 6. Mechanical performance testing The composite solid electrolyte sheet prepared in this comparative example was subjected to bending strength test according to the three-point bending test method described in Example 1.

[0226] Test results show that the flexural strength of the composite solid electrolyte sheet obtained in this comparative example is 51 MPa, which is higher than the 42 MPa of the pure LLNOF solid electrolyte sheet obtained in Comparative Example 1, but lower than the 85 MPa of the composite solid electrolyte sheet obtained in Example 1.

[0227] 7. Assembly and electrochemical performance testing of all-solid-state batteries An all-solid-state battery was assembled using the composite solid-state electrolyte sheet prepared in this comparative example. The positive electrode, negative electrode, assembly method, and test conditions of the all-solid-state battery were the same as those in Example 1.

[0228] The results of the first charge and discharge test are as follows Figure 2 This indicates that the first charge specific capacity of the obtained all-solid-state battery is 195 mAh / g, the first discharge specific capacity is 168 mAh / g, and the first coulombic efficiency is 86.1%.

[0229] Cyclic performance test results show that the capacity retention rate of the obtained all-solid-state battery is 81% after 100 cycles and 68% after 200 cycles.

[0230] 8. Comparative Analysis Compared with Comparative Example 1, the flexural strength of the composite solid electrolyte sheet obtained in this comparative example increased from 42 MPa to 51 MPa, and the capacity retention of the resulting all-solid-state battery after 100 and 200 cycles increased from 78% and 62% to 81% and 68%, respectively. This demonstrates that introducing irregularly shaped hydroxyapatite can improve the mechanical properties of the solid electrolyte sheet and the cycle performance of the all-solid-state battery to a certain extent.

[0231] However, compared to Example 1, the ionic conductivity of the composite solid electrolyte sheet obtained in this comparative example decreased from 1.2 × 10⁻⁶. - 3 S / cm decreased to 8.5×10 -4 The S / cm bending strength decreased from 85MPa to 51MPa; the initial coulombic efficiency of the resulting all-solid-state battery decreased from 90.4% to 86.1%, and the capacity retention after 100 and 200 cycles decreased from 92% and 85% to 81% and 68%, respectively.

[0232] The above results indicate that, under the same conditions of LLNOF composition, hydroxyapatite phase content, and composite material preparation, the morphology of hydroxyapatite and its spatial distribution in the composite material affect the ion transport performance and mechanical properties of the composite solid electrolyte. Compared with irregular hydroxyapatite particles, the hydroxyapatite nanowires in Example 1 can intertwine to form a three-dimensional network structure, and the LLNOF oxyfluorine-based solid electrolyte phase fills the network pores of the three-dimensional network structure. Therefore, the resulting composite solid electrolyte sheet has higher ionic conductivity and flexural strength, and the all-solid-state battery assembled using the composite solid electrolyte sheet also has higher initial coulombic efficiency and cycle capacity retention.

[0233] The test results of the above embodiments and comparative examples are recorded in Table 1.

[0234] Table 1 This invention improves the bonding stability between the oxyfluorine-based solid electrolyte phase and the hydroxyapatite phase by controlling their content, spatial distribution, and interfacial connectivity. The three-dimensional network structure formed by the hydroxyapatite nanowires supports the oxyfluorine-based solid electrolyte phase and allows it to fill the network pores, which is beneficial for improving the structural stability of the composite material and maintaining the continuous distribution of the oxyfluorine-based solid electrolyte phase.

[0235] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An oxyfluoride solid electrolyte composite material, characterized in that, The oxyfluoride solid electrolyte composite material comprises: an oxyfluoride solid electrolyte phase and a hydroxyapatite phase; The general chemical formula of the oxyfluorine-based solid electrolyte phase is Li 2-x La (1+x) / 3 Nb₂O₆F, 0.7≤x≤1; In the oxyfluoride solid electrolyte composite material, the hydroxyapatite phase accounts for 5 wt.% to 40 wt.% by mass, and the oxyfluoride solid electrolyte phase accounts for 60 wt.% to 95 wt.% by mass. The hydroxyapatite phase and the oxyfluorine-based solid electrolyte phase are connected at an interface through Ca-O bonds and / or hydrogen bonds.

2. The oxyfluoride solid electrolyte composite material according to claim 1, characterized in that, The hydroxyapatite phase is hydroxyapatite with the chemical formula Ca. 10 (PO4)6(OH)2; Alternatively, the hydroxyapatite phase is fluorinated hydroxyapatite with the chemical formula Ca. 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2; wherein, the fluorine atoms on the surface of the fluorinated hydroxyapatite and the fluorine atoms in the oxyfluorine solid electrolyte phase form F···F interactions.

3. The oxyfluoride solid electrolyte composite material according to claim 2, characterized in that, The oxyfluoride solid electrolyte composite material has a three-dimensional network-filled structure; The hydroxyapatite phase is in the form of nanowires with a diameter of 50-200 nm and an aspect ratio of ≥30. Multiple hydroxyapatite nanowires intertwine to form a three-dimensional network structure; the oxyfluorine-based solid electrolyte phase fills the network pores of the three-dimensional network structure.

4. The oxyfluoride solid electrolyte composite material according to claim 2, characterized in that, The oxyfluoride solid electrolyte composite material has a core-shell structure; The oxygen-fluorine solid electrolyte phase forms the core, and the hydroxyapatite phase forms the shell. The thickness of the shell layer is 5-100 nm; The shell is a porous shell with multiple pores that penetrate the shell and / or are interconnected to form lithium-ion transport channels.

5. A method for preparing the oxyfluoride solid electrolyte composite material according to claim 3, characterized in that, The method includes: Preparation of hydroxyapatite nanowires; the chemical formula of the hydroxyapatite is Ca. 10 (PO4)6(OH)2 or Ca 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2; The hydroxyapatite nanowires are dispersed in a solvent, and an oxyfluorine solid electrolyte precursor or oxyfluorine solid electrolyte powder is added and mixed to obtain a mixed dispersion. The solvent in the mixed dispersion is removed by evaporation to obtain the composite precursor; The composite precursor is subjected to heat treatment to obtain the oxyfluoride solid electrolyte composite material.

6. The preparation method according to claim 5, characterized in that, After dispersing the hydroxyapatite nanowires in the solvent, the method further includes: performing ultrasonic treatment for 30 min to 60 min; After adding the oxygen-fluorine solid electrolyte precursor or oxygen-fluorine solid electrolyte powder, the mixing specifically includes: stirring and mixing for 2 to 6 hours; The solvent includes one or more of ethanol, isopropanol, or deionized water; The heat treatment temperature is 600℃~900℃, and the time is 4h~12h.

7. A method for preparing the oxyfluoride solid electrolyte composite material according to claim 3, characterized in that, The method includes: Prepare an oxygen-fluorine solid electrolyte sol precursor solution containing lithium, lanthanum, niobium and fluorine sources; Hydroxyapatite nanowires were dispersed in the oxyfluorine-based solid electrolyte sol precursor solution to obtain a mixed sol; the chemical formula of the hydroxyapatite is Ca. 10 (PO4)6(OH)2 or Ca 10 (PO4)6(OH) 2-y F y , 0.6≤y≤2; The mixed sol was heated and gelled to obtain a composite gel containing the hydroxyapatite nanowires; The composite gel was heat-treated at 500℃~800℃ to obtain the oxyfluoride solid electrolyte composite material.

8. A method for preparing the oxyfluoride solid electrolyte composite material according to claim 4, characterized in that, The method includes: Oxyfluoride solid electrolyte particles are placed in a fluidized bed reactor; A reaction precursor is introduced into the fluidized bed reactor, and chemical vapor deposition or atomic layer deposition is used to deposit the reaction precursor on the surface of the oxygen-fluorine solid electrolyte particles to form a hydroxyapatite shell coating the oxygen-fluorine solid electrolyte particles, thereby obtaining an oxygen-fluoride solid electrolyte composite material with a core-shell structure. The reaction precursors include: calcium source precursors, phosphorus source precursors, hydroxyl-oxygen source precursors, and precursors including or excluding fluorine source precursors.

9. A solid electrolyte component, characterized in that, The solid electrolyte component includes: a solid electrolyte membrane, a solid electrolyte sheet, or a solid electrolyte layer; The solid electrolyte component is mainly composed of the oxyfluoride solid electrolyte composite material described in any one of claims 1-4.

10. An all-solid-state lithium battery, characterized in that, The all-solid-state lithium battery includes the oxyfluoride solid electrolyte as described in any one of claims 1-4.

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