Solution synthesis of lithium-sulfur argyrodite particles

Abstract

The present invention relates to a method for synthesizing lithium argyrodite particles of the formula Li x ( wherein x is 1-8), a phosphorous reactant Rp selected from the group consisting of P2S5, P4S 10 , P4S9 and P4S 9+n ( wherein n is 0-1) and a halide selected from the group consisting of LiX and PSX3 and optionally a phosphorous or halogen containing oxygen containing reactant selected from the group consisting of P2O5, LiClO4, LiBrO4, LiIO4, 7‑(a+b) PS 6‑(a+b+c) O c X a Q b wherein X and Q are two different halogens selected from the group consisting of F, Cl, Br, I; O is an oxygen atom, wherein 1≤a+b<2, c is 0-0.25 (inclusive), a and b are not simultaneously zero, by generating an intermediate solvated complex Li3PS4· solvent, centrifuging, re-dispersing the centrifuged phase in anhydrous solvent, then filtering, washing, drying and heat treating the intermediate compound.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage via lithium batteries, and more specifically, to all-solid-state batteries using an inorganic phase of silver-germanium sulfide as the solid electrolyte. More specifically, this invention relates to solution-based preparation of the silver-germanium sulfide phase and aims to provide methods related to product quality, preparation time, and industrial scale-up. Background Technology

[0002] Developing industrially feasible methods for preparing silver-germanium sulfide phases with good ionic conductivity is crucial for the widespread adoption of all-solid-state batteries. Furthermore, for these methods to be feasible, they must be modifiable and scaled up to industrial scale at an acceptable cost.

[0003] Initially, as described in patent applications and patents such as US20170222257 A1, US8075865 BB, and US09899701 B2, the silver-germanium sulfide phase was obtained via solid-based preparation methods through melt quenching. These methods are time-consuming and difficult to scale up industrially. Recently, preparation methods described by mechanical synthesis have emerged, which typically yield micron-sized particles with good electrical conductivity, compared to melt-quenching methods. These methods currently dominate, involving a grinding sequence lasting several days, followed by heat treatment at high temperatures, particularly as described in patent applications and patents US11264642 BB, CN113097560 A, US11245131 BB, and US11699809 B2, and publication Phys. Status Solidi A208, No.8 (2011).

[0004] Liquid-based grinding methods have also been described, which can shorten grinding time and reduce particle size, as described in patent applications WO2022162085 A, CN113410513 A, CN109638347 A, and US11258057 BB. Mechanosynthesis techniques require equipment such as planetary mills, which cannot be scaled up industrially.

[0005] Alternative solution preparation methods have also been described. For example, the authors of ACS Energy Lett. 2019, 4, 265-270 describe a method for preparing lithium sulfide germanium ore (LiPSX) involving the formation of an intermediate Li3PS4·2THF in a tetrahydrofuran (THF) solvent (24 hours at room temperature), followed by the addition of an ethanol solution containing LiX (I, Br, and Cl) and Li2S. After stirring overnight, the solution is evaporated under reduced pressure and then dried under reduced pressure at 140 °C for 20 hours. Finally, the powder is densified by pressing and baked under reduced pressure at 550 °C for 6 hours.

[0006] Other patents and patent applications (US10777846 BB; US20210242493 A1, CN114455613 A, US10777846 BB) describe the preparation of silver-sulfur germanium ore by reacting Li₂S, P₂S₅, and Liₓ in a polar solvent at room temperature. The solvent can be, for example, an alcohol, carbonate, ester, ether, nitrile, or a mixture thereof. After evaporating the solvent under reduced pressure (evaporating at 25-50°C for 1 to 3 hours), the powder is recovered and preferably dried under reduced pressure (multiple drying sequences may be used). The powder is then heat-treated at 350°C to 550°C for 1 to 5 hours.

[0007] In an attempt to accelerate reaction kinetics, other solution preparation methods have been developed, particularly by altering operating conditions such as temperature, pressure, stirring methods, and solvent combinations: see in particular patent application WO2021 / 099625, which proposes cooling to -80°C, or patent US10879559, which combines two solvents: a polar solvent and a saturated or unsaturated hydrocarbon. Summary of the Invention

[0008] Surprisingly, the applicant has discovered that lithium-sulfur silver-germanium ore particles can be prepared by a specific solution method that does not involve expensive equipment or steps, has a short reaction time, and can therefore be scaled up to an industrial scale.

[0009] This invention relates to lithium reactants Li2S x (where x is 1-8), selected from P2S5, P4S 10 P4S9 and P4S 9+n Phosphorus reactant Rp (where n is 0-1) and halides selected from LiX and PSX3, and optionally oxygen-containing phosphorus reactants or halogen reactants selected from P2O5, LiClO4, LiBrO4, and LiIO4, are used to synthesize a phosphorus reactant with the formula Li 7-(a+b) PS 6-(a+b+c) O c X a Q b A method for preparing lithium-sulfur silver-germanium ore particles, wherein X and Q are two different halogen elements selected from F, Cl, Br and I, O is an oxygen atom, where 1 ≤ a + b < 2, c is 0-0.25 (inclusive), and a and b are not simultaneously zero, the method comprising at least the following steps under an inert atmosphere: A) At a temperature of 50°C to 150°C, a lithium reactant, a halide, and optionally an oxygen-containing halogen reactant pre-suspended in at least one first polar solvent (solvent 1) are contacted with a suspension containing at least a phosphorus reactant and optionally an oxygen-containing phosphorus reactant in at least one second polar solvent (solvent 2, which may be similar in nature to solvent 1), and under reflux conditions as a reaction with an additional solid reactant, Li₂S.x A mixture of LiX and optional oxygen-containing reactants is formed as a solvated complex of Li3PS4·solvent to form a suspension intermediate, wherein the volume ratio of solvent 1 to solvent 2 is 1-4, preferably 0.5-1.5, and the relative proportions of different reactants are determined according to the chemical formula of the final compound in the form of lithium-sulfur silver-germanium ore particles. 7-(a+b) PS 6-(a+b+c) O c X a Q b Select according to stoichiometry; B) Centrifuge, redisperse the centrifuged phase in a third anhydrous solvent that is the same as or different in properties from the first solvent and the second solvent, and then filter and wash the intermediate; C) Drying at a temperature of 25°C to 150°C for 1 to 10 hours; and D) Heat treatment, at a temperature of 300°C to 600°C for 1 to 10 hours.

[0010] According to one implementation scheme, 1≤a+b≤1.8, especially 1≤a+b≤1.6, and preferably 1≤a+b≤1.5.

[0011] According to the first implementation scheme, in step A): A1) Lithium reactants Li2S x Li₂S (preferably Li₂S), halides (Li₃ or PSX₃, preferably Li₃), and optional oxygen-containing halogen reactants are dispersed in a first polar solvent (solvent 1) under stirring, wherein the lithium reactant Li₂S x The mass concentration in the solvent is 10 g / L-100 g / L, preferably 30 g / L-70 g / L; the mass concentration of the halide LiX or PSX3 in the solvent is 1 g / L-100 g / L, preferably 5 g / L-80 g / L; the mass concentration of the oxygen-containing halogen reactant is 0.1 g / L-10 g / L; and the resulting suspension can be heated at 25°C to 50°C, preferably 30°C to 40°C. A2) The phosphorus reactant Rp can then be dispersed in a second polar solvent (solvent 2) under stirring, wherein the mass concentration of the phosphorus reactant in the solvent is 10 g / L-100 g / L, preferably 30 g / L-80 g / L, more preferably 35 g / L-70 g / L, and the resulting suspension is heated at 50°C to 150°C, preferably 90°C to 110°C. A3) A solution of lithium reactants and halides (preferably Li2S and LiX) can be gradually added to a suspension of temperature-activated phosphorus reactants (preferably P2S5) over 1 to 6 minutes, preferably 2 to 4 minutes, and the resulting suspension can be refluxed under an inert atmosphere and with stirring for 1 to 24 hours, preferably 2 to 8 hours.

[0012] In the second embodiment, in step A): A1) The lithium reactant in the first part, Li2S x Li2S (preferably Li2S) and phosphorus reactant (preferably P2S5) are dispersed in a first polar solvent (solvent 1) under stirring. The mass concentration of the lithium reactant (preferably Li2S) in the solvent is 3 g / L-30 g / L, preferably 5 g / L-20 g / L, and the mass concentration of the phosphorus reactant (preferably P2S5) in the solvent is 10 g / L-100 g / L, preferably 30 g / L-80 g / L, more preferably 35 g / L-70 g / L. The resulting suspension can be heated at 25°C to 50°C, preferably 30°C to 40°C, to form a solution. A2) The lithium reactant in the second part, Li2S x The lithium reactant Li₂S is dispersed in a second polar solvent (solvent 2) with halides LiX or PSX₃ under stirring. x The mass concentration in the solvent is 10 g / L-80 g / L, preferably 5 g / L-70 g / L, and the mass concentration of the halide LiX or PSX3 is 1 g / L-100 g / L, preferably 5 g / L-80 g / L. The resulting suspension can be heated at 50°C to 150°C, preferably 90°C to 110°C. A3) The solution of lithium reactants and phosphorus reactants (preferably Li2S and P2S5) can then be gradually added to the suspension of lithium reactants and halides (preferably Li2S+LiX) over 1 to 6 minutes, preferably 2 to 4 minutes, and the resulting suspension can be refluxed under an inert atmosphere and with stirring for 1 to 24 hours, preferably 2 to 8 hours.

[0013] The intermediate in the form of a solvated complex can be recovered as a wet powder by centrifugation at 1000 to 10000 rpm for 5 to 30 minutes, redispersing it in a third anhydrous solvent, and then washing it on a glass frit with the same or different anhydrous solvents.

[0014] The drying in step C) can be carried out at 10 -2 Up to 10 -3 The test was conducted for 2 to 6 hours at a pressure of mbar and a temperature of 40°C to 80°C.

[0015] Heat treatment step D) can be performed after drying in step C), which is carried out under an inert gas flow or at 10 -2 Up to 10 -3 The process was carried out in a traversed bed reactor under reduced pressure of mbar.

[0016] The inert gas can be argon, nitrogen, or a mixture of both, and the gas flow rate can be 1 L / g / h to 15 L / g / h, preferably 8 to 12 L / h / g.

[0017] Before suspension, Li₂S can be suspended by dry mechanical milling, solution mechanical milling, or dissolution-precipitation in a solvent. x The reactants are pretreated.

[0018] The polar solvent, whether it is the first solvent (solvent 1) or the second solvent (solvent 2), may be selected from cyclic or straight-chain ethers, esters, nitriles, alcohols and thiols.

[0019] According to the synthesis method of the present invention, wherein X=Cl, a=1, b=0, c=0, the sulfosilver germanium mineral phase Li6PS5Cl can be obtained.

[0020] According to the synthesis method of the present invention, wherein X=Cl, a=1.5, b=0, c=0, the Li-silver-germanium mineral phase can be obtained. 5.5 PS 4.5 Cl 1.5 .

[0021] According to the synthesis method of the present invention, wherein X = Cl, Q = Br, a = 0.5, b = 0.5, and c = 0, the sulfide-silver-germanium mineral phase Li6PS5Cl can be obtained. 0.5 Br 0.5 .

[0022] Another subject of this invention is the silver-sulfur germanium mineral phase Li6PS5Cl or the silver-sulfur germanium mineral phase Li. 5.5 PS 4.5 Cl 1.5 Or sulfur-silver-germanium mineral phase Li6PS5Cl 0.5 Br 0.5 In particular, it is obtained by the method according to the invention.

[0023] Other subjects of the invention are the use of these phases in forming portions of solid electrolytes (particularly for manufacturing battery-type electrochemical devices), and devices comprising these phases. Attached Figure Description

[0024] Figure 1 A block diagram showing the synthesis steps according to the present invention is shown.

[0025] Figure 2 The Raman spectrum of the Li6PS5Cl phase obtained in Example 1 is shown.

[0026] Figure 3 The diffraction pattern of the Li6PS5Cl phase obtained in Example 1 is shown.

[0027] Figure 4 SEM images of the Li6PS5Cl particles obtained in Example 1 are shown.

[0028] The X-axis of the Raman spectrum is in cm -1 Raman displacement is expressed in units of 1, and the Y-axis is expressed in arbitrary units (au).

[0029] SEM stands for Scanning Electron Microscopy.

[0030] The Y-axis of the diffraction pattern is expressed in arbitrary units (au).

[0031] Description of the implementation plan This invention relates to the preparation of products having the formula Li 7-(a+b) PS 6-(a+b+c) O c X a Q b A novel method for synthesizing silver-germanium sulfide phases, wherein X and Q are two different halogen elements selected from F, Cl, Br and I; O is an oxygen atom, wherein 1≤a+b<2, c is 0-0.25 (inclusive), and a and b are not simultaneously zero. The synthesis method has a short reaction time and can be scaled up to industrial scale.

[0032] When c=0, the silver-sulfur germanium ore phase has the formula Li 7-(a+b) PS 6-(a+b) X a Q b .

[0033] reactants The reactants used in the method for synthesizing silver-germanium ore according to the present invention are as follows.

[0034] For lithium reactants, the preferred reactants are Li₂S or Li₂S₂. x Where x is 2-8. Throughout the specification, for simplicity, the lithium reactant is represented as Li₂S. x , where x is 1-8.

[0035] For phosphorus reactants, the preferred reactants are P2S5 and P4S. 10 P4S9 and P4S 9+n , where n is 0-1.

[0036] For oxygen-containing phosphorus reactants, the preferred reactant is P2O5.

[0037] For halide reactants, preferred reactants are LiX (where X = F, Cl, Br, I) and / or PSX3 (where X = F, Cl, Br, I).

[0038] For oxygen-containing halogen reactants, the preferred reactants are LiClO4, LiBrO4 and LiIO4.

[0039] All methods for preparing the reactants described in this application are applicable to the method for preparing the sulfosilver germanium phase according to the present invention.

[0040] Advantageously, it is possible to react with Li2S x Preprocessing is performed.

[0041] In the case of Li2S, the pretreatment may be dry or solution mechanical milling (planetary), or dissolution-precipitation in ethanol, or any other method known to those skilled in the art.

[0042] Polar solvents are used to disperse and / or activate reactants. Advantageously, one solvent or a combination of solvents can be used to disperse and activate reactants, especially: - Solvents (solvent 1) used to disperse lithium reactants and halides, preferably Li₂S and LiX: cyclic or linear ethers (e.g., THF and dimethoxyethane, dioxane, dioxolane, dioxolane, dibutyl ether, anisole), esters (alkyl acetates, e.g., butyl acetate, ethyl acetate, tert-butyl acetate, methyl acetate; isobutyl isobutyrate, dimethyl glutarate, diethyl glutarate, ethyl benzoate, methyl benzoate), nitriles (e.g., acetonitrile, propionitrile, butyronitrile, benzonitrile), thiols (e.g., propanethiol, butanethiol, pentanylthiol, thiophenol), - Solvents used to activate phosphorus reactants, such as P2S5 (solvent 2): cyclic or linear ethers (e.g., THF and dimethoxyethane, dioxane, dioxolane, dioxolane, dibutyl ether, anisole), esters (alkyl acetates, such as butyl acetate, ethyl acetate, tert-butyl acetate, methyl acetate; isobutyl isobutyrate, dimethyl glutarate, diethyl glutarate, ethyl benzoate, methyl benzoate), nitriles (e.g., acetonitrile, propionitrile, butyronitrile, benzonitrile), thiols (e.g., propanethiol, butanethiol, pentylenetetrol, thiophenol), alcohols (e.g., methanol, ethanol, isopropanol, tert-butanol), amines (butylamine, pyridine, ethylenediamine, piperidine). Solvent 3, the so-called washing solvent, is preferably selected from polar, nonpolar, or aprotic solvents and is not an alcohol. For example, it can be tetrahydrofuran (THF) or acetonitrile (ACN).

[0043] All solvents are preferably anhydrous.

[0044] As shown in the solvent list above, according to one embodiment of the present invention, solvent 1 and solvent 2 may be the same.

[0045] According to another preferred embodiment of the invention, different types of solvents are selected.

[0046] One possible option is, for example, a combination of THF as solvent 1 and butyl acetate as solvent 2, or a combination of THF as solvent 1 and isobutyl isobutyrate as solvent 2.

[0047] The preparation method comprises at least four steps. All operations are performed under an inert atmosphere.

[0048] • The step of forming a suspended Li3PS4 solvent intermediate (solventized complex) under reflux conditions in the presence of other solid reactants (e.g., Li2S and LiX).

[0049] • Through centrifugation and filtration washing steps.

[0050] • Drying, preferably drying under reduced pressure.

[0051] • Heat treatment steps.

[0052] The relative proportions of the different reactants are selected by those skilled in the art according to the stoichiometric ratio of the chemical formula of the target final silver-germanium sulfide compound. Advantageously, for each reactant: Li2S x The mass concentration in the solvent can be 30 g / L-70 g / L. The mass concentration of phosphorus reactants (e.g., P2S5) in the solvent can be 35 g / L-70 g / L. The mass concentration of LiCl in the solvent can be 5 g / L-30 g / L. The mass concentration of LiBr in the solvent can be 15 g / L-55 g / L. The mass concentration of LiI in the solvent can be 30 g / L-80 g / L. The mass concentration of PSCl3 in the solvent can be 1 g / L-20 g / L. The mass concentration of LiClO4 in the solvent can be 0.1 g / L-5 g / L. The mass concentration of LiBrO4 in the solvent can be 0.1 g / L-5 g / L. The mass concentration of LiIO4 in the solvent can be 0.5 g / L-10 g / L. The mass concentration of P2O5 in the solvent can be 0.1 g / L to 5 g / L.

[0053] As a non-limiting example, a method using reactants Li2S and LiX, as well as P2S5, is described below.

[0054] First step: The first step can be performed in two alternative ways.

[0055] Figure 1 (Top) shows the various steps of forming the silver-sulfur germanium phase compound according to the first embodiment.

[0056] Figure 1 (Lower section) shows the different steps for forming the sulfide-silver-germanium phase compound according to the second embodiment.

[0057] exist Figure 1 In the middle, (1) corresponds to suspension, (2) corresponds to reflux, (3) corresponds to reflux, (4) corresponds to washing, and (5) corresponds to heat treatment.

[0058] for Figure 1 The upper part, box (1) corresponds to suspending Li reactants and P reactants and optional oxygen-containing phosphorus reactants, and box (2) corresponds to refluxing Li reactants and X reactants and optional oxygen-containing halogen reactants.

[0059] for Figure 1 The lower part, box (1) corresponds to suspending Li reactant and X reactant and optional oxygen-containing halogen reactant, and box (2) corresponds to refluxing P reactant and optional oxygen-containing phosphorus reactant.

[0060] Reference Figure 1 Describe the steps below.

[0061] Step 1: Formation of a suspended intermediate (reflux) The synthesis method according to the invention can overcome the kinetic limitations during intermediate formation by activating the phosphorus reactant (e.g., P2S5). In fact, the reactant is P4S... 10 The adamantane cage form restricts its reaction with Li₂S. Activation of the P₂S₅ reactant involves heating the adamantane cage to dedimerize it. To facilitate a rapid reaction, pre-suspended lithium and halide reactants (here, Li₂S and LiX) are thermally added to a suspension containing the phosphorus reactant P₂S₅.

[0062] Step 1.1 The first stage can be achieved, for example, by dispersing the lithium reactant Li₂S and the halide LiX in a first polar solvent (solvent 1) in a Schlenck flask to form a suspension. The dispersion is advantageously carried out in an ultrasonic bath at 25°C to 50°C, preferably 30°C to 40°C, for 1 minute to 120 minutes, preferably 10 to 50 minutes. The mass concentration of Li₂S in the solvent is 10 g / L to 100 g / L, preferably 30 g / L to 70 g / L. The mass concentration of LiX is 1 g / L to 100 g / L, preferably 5 g / L to 35 g / L when X = Cl, preferably 10 g / L to 60 g / L when X = Br, and preferably 20 g / L to 80 g / L when X = I.

[0063] Step 1.2 In the second stage, the reactant P2S5 can be dispersed in a second polar solvent (solvent 2, which may be of the same type as solvent 1) in a three-necked flask equipped with a water condenser. The suspension is heated at 50°C to 150°C, preferably 90°C to 110°C, with stirring. The mass concentration of P2S5 in the solvent is 10 g / L to 100 g / L, preferably 30 g / L to 80 g / L, and more preferably 35 g / L to 70 g / L.

[0064] Step 1.3 Advantageously, the Li₂S + Liₓ suspension is transferred to a device (e.g., a dropping funnel) that allows for gradual addition to the activated P₂S₅ suspension, adding it dropwise to the temperature-activated P₂S₅ suspension. The addition time is from 1 minute to 6 minutes, preferably 2 to 4 minutes.

[0065] The resulting suspension is refluxed for 1 to 24 hours, preferably 2 to 8 hours, at a temperature of 50 to 150°C (preferably 100°C) under an inert atmosphere. The inert atmosphere can be dynamic (constant flow rate) or static, and the gas can be argon, nitrogen, or a mixture of both. The molar ratio of Li₂S / P₂S₅ is 3-6, preferably 4-5. The molar ratio of Li₃ / P₂S₅ is 0.5-3.5, preferably 1-3. The volume ratio of solvent 1 / solvent 2 is 0.1-4, preferably 0.5-1.5.

[0066] According to the second implementation plan of step 1 (refer to...) Figure 1 The following description, using reactants Li₂S and Liₓ and P₂S₅ as examples: Alternative step 1.1 The first sub-step can be performed, for example, in a Schlenck flask, by dispersing the lithium reactant Li₂S and phosphorus reactant P₂S₅ from the first portion in a first polar, preferably aprotic, solvent (solvent 1) to form a solution. The mass concentration of Li₂S in the solvent is 3 g / L to 30 g / L, preferably 5 g / L to 20 g / L. The mass concentration of P₂S₅ in the solvent is 10 g / L to 100 g / L, preferably 30 g / L to 80 g / L, more preferably 35 g / L to 70 g / L.

[0067] Alternative step 1.2 The second sub-step can be achieved, for example, by dispersing the lithium reactant Li₂S and halide LiX from the second portion in a second polar solvent (solvent 2, which may be of the same type as solvent 1) in a three-necked flask equipped with a water condenser to form a suspension. The suspension is heated at 50°C to 150°C, preferably 90°C to 110°C, with stirring. The mass concentration of Li₂S in the solvent is 10 g / L to 80 g / L, preferably 20 g / L to 70 g / L. The mass concentration of LiX is 1 g / L to 100 g / L, preferably 5 g / L to 35 g / L when X = Cl, preferably 10 g / L to 60 g / L when X = Br, and preferably 20 g / L to 80 g / L when X = I.

[0068] Alternative step 1.3 Finally, advantageously, the Li₂S and P₂S₅ solution is transferred to a device (e.g., a dropping funnel) that allows for gradual addition to the Li₂S and Liₓ suspension to add dropwise to the Li₂S + Liₓ suspension. The time for adding the Li₂S and P₂S₅ solution is from 1 to 6 minutes, preferably 2 to 4 minutes. Under an inert atmosphere, the resulting suspension is refluxed at a temperature of 50 to 150°C (preferably 100°C) for 1 to 24 hours, preferably 2 to 8 hours. The inert atmosphere can be dynamic (constant flow rate) or static, and the gas can be argon or nitrogen or a mixture of both. The molar ratio of Li₂S / P₂S₅ is 3-6, preferably 4-5. The molar ratio of Liₓ / P₂S₅ is 0.5-3.5, preferably 1-3. The volume ratio of solvent 1 to solvent 2 is 0.1-4, preferably 0.5-1.5.

[0069] Step 2: Washing of the intermediate (solvated complex) At the end of the reaction, the intermediate (i.e., the solvated complex of Li3PS4·solvent) reacts with the other solid reactant Li2S xThe intermediate is in suspension form in a solvent mixture (a mixture of LiX and optionally oxygen-containing reactants). The intermediate is recovered by centrifugation (advantageously at 1000 to 10000 rpm for 5 to 30 minutes, here 20 minutes at 10000 rpm) and redispersed in a third anhydrous solvent (the same or different from the previous solvent), then washed, advantageously on glass frit with the same or different anhydrous solvent, to obtain a wet powder.

[0070] Step 3: Drying The obtained powder is dried, preferably under reduced pressure (typically 10) at a temperature of 25°C to 150°C, more preferably 40°C to 80°C. -2 Up to 10 -3 Drying (mbar) for 1 to 10 hours, preferably 2 to 6 hours.

[0071] Step 4: Heat treatment Heat treatment is preferably performed under an inert gas flow or under reduced pressure (usually 10). -2 Up to 10 -3 The process (mbar) is carried out in a cross-flow bed reactor. The inert gas can be argon, nitrogen, or a mixture of both. The gas flow rate is 1 L / g / h to 15 L / g / h, preferably 8 to 12 L / h / g. This configuration effectively removes the solvent. The treatment temperature is advantageously 300°C to 600°C, lasting from 1 hour to 10 hours. The treatment conditions depend on the nature of the phase being treated.

[0072] Characterization techniques SEM images were obtained using a scanning electron microscope (SEM) (model Supra40, manufactured by Zeiss). ® (For sale) Filmed. Accelerating voltage is 2kV.

[0073] Raman analysis can be used to observe PS4 in detail. 3- The presence of a phase, which results in the good ionic conductivity of thiophosphate, was determined by the Raman absorption wavelength of the tetrahedron. Raman spectra were acquired on a Renishaw spectrometer equipped with a confocal lens and a 532 nm laser. The sample was pre-encapsulated in an impermeable cell. The spectral acquisition parameters were as follows: power 3.9 mW, time 100 s.

[0074] XRD analysis was used to monitor the formation of the characteristic crystal structure of silver-germanium sulfide. Diffraction patterns were acquired on a Bruker D4 diffractometer (40 kV, 40 mA) using a copper anode (Kα1 = 1.54060 Å; Kα2 = 1.54439 Å). The samples were pre-encapsulated in two Kapton sheets sealed with vacuum grease.

[0075] The ionic conductivity of the sample was determined by electrochemical impedance spectroscopy in a temperature-controlled cell (model ASC-T, manufactured by SphereEnergy). ® (For sale) Measurements were taken between two blocking electrodes. The solid electrolyte was compacted directly between the two electrodes at a pressure of 4 tons / cm². Impedance measurements were performed using Biologic. ® The MTZ-35 impedance meter operates in the range of 30MHz to 1Hz with an amplitude of 10mV relative to a voltage of 0V and a temperature of 30°C. Example

[0076] Example 1: Preparation of Li6PS5Cl phase according to the present invention In a Schlenck tube, 0.45 g of Li₂S and 2.17 g of P₂S₅ were dispersed in 50 mL of tetrahydrofuran (THF). The tube was then sonicated at 35 °C for 30 min, and the resulting solution was transferred to a dropping funnel. In a three-necked flask, 1.70 g of weighed Li₂S and 0.85 g of LiCl were dispersed in 50 mL of butyl acetate (BA). The suspension of Li₂S and LiCl was heated to 100 °C in a reflux reflux apparatus. The solution of Li₂S and P₂S₅ was then added dropwise to the solution of Li₂S and LiCl over 3 min. After stirring at 100 °C for 4 hours, the flask was cooled to room temperature. The suspension was then centrifuged at 10,000 rpm for 20 min. The precipitate was redispersed in tetrahydrofuran (THF) and washed with THF on a glass frit to obtain a wet white powder. The powder was then dried under reduced pressure at 50 °C for 5 h. The obtained powder was then baked in argon gas at a flow rate of 10 L / h / g at 550 °C for 4 hours.

[0077] Through Raman spectroscopy ( Figure 2 X-ray diffraction pattern Figure 3 ), scanning microscope ( Figure 4 The obtained powder was characterized by impedance spectroscopy and other methods. Figure 2 The Raman spectrum of the obtained phase is shown, with 424 cm⁻¹ as an example. -1 The vibrational peak at that location is the PS4³ of the lithium-sulfur-silver-germanium mineral phase. - Characteristic peaks of the unit. Figure 3 It was confirmed that the crystal structure of the obtained phase mainly corresponds to that of lithium-sulfur silver-germanium ore. Figure 4 The Li6PS5Cl particles obtained before heat treatment are shown. The ionic conductivity measured at 30 °C is 0.9 mS / cm.

[0078] Example 2: Preparation of Li6PS5Cl according to the present invention 0.5 Br 0.5 Mutually In a Schlenck tube, 0.41 g of Li₂S and 1.98 g of P₂S₅ were dispersed in 50 mL of tetrahydrofuran (THF). The tube was then sonicated at 35 °C for 30 min, and the resulting solution was transferred to a dropping funnel. In a three-necked flask, 1.6 g of Li₂S, 0.38 g of LiCl, and 0.78 g of LiBr were dispersed in 50 mL of butyl acetate (BA). The suspension of Li₂S, LiCl, and LiBr was heated to 100 °C in a reflux reflux apparatus. The solution of Li₂S and P₂S₅ was then added dropwise to the solution of Li₂S, LiCl, and LiBr over 3 min. After stirring at 100 °C for 4 hours, the flask was cooled to room temperature. The suspension was then centrifuged at 10,000 rpm for 20 min. The precipitate was redispersed in tetrahydrofuran (THF) and then washed with THF on a glass frit to obtain a wet white powder. The powder was then dried under reduced pressure at 50°C for 5 hours. The resulting powder was then baked at 550°C for 4 hours in argon gas at a flow rate of 10 L / h / g.

[0079] Through Raman spectroscopy ( Figure 2 X-ray diffraction pattern Figure 3 The obtained powder was characterized by impedance spectroscopy and other methods. Figure 2 The Raman spectrum of the obtained phase is shown, with 425 cm⁻¹ as an example. -1 The vibrational peak at that location is the PS4³ of the lithium-sulfur-silver-germanium mineral phase. - Characteristic peaks of the unit. Figure 3 The crystal structure of the obtained phase was confirmed to primarily correspond to that of lithium-sulfur silver-germanium ore. The ionic conductivity measured at 30 °C was 1.8 mS / cm.

[0080] Example 3: Preparation of Li according to the present invention 5.5 PS 4.5 Cl 1.5 Mutually In a Schlenck tube, 0.44 g of Li₂S and 2.15 g of P₂S₅ were dispersed in 50 mL of tetrahydrofuran (THF). The tube was then sonicated at 35 °C for 30 min, and the resulting solution was transferred to a dropping funnel. In a three-necked flask, 0.44 g of weighed Li₂S and 1.23 g of LiCl were dispersed in 50 mL of butyl acetate (BA). The suspension of Li₂S and LiCl was heated to 100 °C in a reflux apparatus. The solution of Li₂S and P₂S₅ was then added dropwise to the solution of Li₂S and LiCl over 3 min. After stirring at 100 °C for 4 hours, the flask was cooled to room temperature. The suspension was then centrifuged at 10,000 rpm for 20 min. The precipitate was redispersed in tetrahydrofuran (THF) and washed with THF on a glass frit to obtain a wet white powder. The powder was then dried under reduced pressure at 50 °C for 5 h. The resulting powder was then baked in argon gas at a flow rate of 10 L / h / g at 550 °C for 4 hours.

[0081] Through Raman spectroscopy ( Figure 2 X-ray diffraction pattern Figure 3 The obtained powder was characterized by impedance spectroscopy and other methods. Figure 2 The Raman spectrum of the obtained phase is shown, with 426 cm⁻¹ as an example. -1 The vibrational peak at that location is the PS4³ of the lithium-sulfur-silver-germanium mineral phase. - Characteristic peaks of the unit. Figure 3 The crystal structure of the obtained phase was confirmed to primarily correspond to that of lithium-sulfur silver-germanium ore. The ionic conductivity measured at 30 °C was 2.5 mS / cm.

[0082] Example 4: Preparation of Li6PS according to the present invention 4.875 O 0.125 Cl 1.5 Mutually In a Schlenck tube, 0.44 g of Li₂S, 2.06 g of P₂S₅, and 0.07 g of P₂O₅ were dispersed in 50 mL of tetrahydrofuran (THF). The tube was then sonicated at 35 °C for 30 min, and the resulting solution was transferred to a dropping funnel. In a three-necked flask, 0.44 g of weighed Li₂S and 1.23 g of LiCl were dispersed in 50 mL of butyl acetate (BA). The suspension of Li₂S and LiCl was heated to 100 °C in a reflux apparatus. The solution of Li₂S and P₂S₅ was then added dropwise to the solution of Li₂S and LiCl over 3 min. After stirring at 100 °C for 4 hours, the flask was cooled to room temperature. The suspension was then centrifuged at 10,000 rpm for 20 min. The precipitate was redispersed in tetrahydrofuran (THF) and then washed with THF on a glass frit to obtain a wet white powder. The powder was then dried under reduced pressure at 50°C for 5 hours. The resulting powder was then baked at 550°C for 4 hours in argon gas at a flow rate of 10 L / h / g.

[0083] Through Raman spectroscopy ( Figure 2 X-ray diffraction pattern Figure 3 The obtained powder was characterized by impedance spectroscopy and other methods. Figure 2 The Raman spectrum of the obtained phase is shown, where 424 cm⁻¹ -1 The vibrational peak at that location is the PS4³ of the lithium-sulfur-silver-germanium mineral phase. - Characteristic peaks of the unit. Figure 3 The crystal structure of the obtained phase was confirmed to primarily correspond to that of lithium-sulfur silver-germanium ore. The ionic conductivity measured at 30 °C was 1.3 mS / cm.

[0084] Table 1 Example <![CDATA[ Ionic conductivity at 30℃ (mS / cm) ]]> <![CDATA[1 Li6PS5Cl]]> 0.9 <![CDATA[2 Li6PS5Cl 0.5 Br 0.5 ]]> 1.8 <![CDATA[3 Li 5.5 PS 4.5 Cl 1.5 ]]> 2.5 <![CDATA[4 Li6PS 4.875 Oh 0.125 Cl 1.5 ]]> 1.3 .

[0085] As can be seen, the ionic conductivity of these four embodiments is close to or greater than 1 mS / cm, thus achieving a conductivity level that is particularly attractive for applications in battery electrolytes.

Claims

1. From lithium reactant Li₂S x Where x is 1-8, selected from P2S5 and P4S 10 P4S9 and P4S 9+n Phosphorus reactant Rp, where n is 0-1, and halides selected from LiX and PSX3, and optionally oxygen-containing phosphorus reactants or halogen reactants selected from P2O5, LiClO4, LiBrO4 and LiIO4, are used to synthesize a phosphorus reactant or halogen reactant with the formula Li 7-(a+b) PS 6-(a+b+c) O c X a Q b A method for preparing lithium-sulfur silver-germanium ore particles, wherein X and Q are two different halogen elements selected from F, Cl, Br and I, O is an oxygen atom, where 1 ≤ a + b < 2, c is 0-0.25 including end values, and a and b are not simultaneously zero, the method comprising at least the following steps under an inert atmosphere: A) At a temperature of 50°C to 150°C, a lithium reactant, a halide, and optionally an oxygen-containing halogen reactant pre-suspended in at least one first polar solvent (solvent 1) are contacted with a suspension containing at least a phosphorus reactant and optionally an oxygen-containing phosphorus reactant in at least one second polar solvent (solvent 2, which may be similar in nature to solvent 1), and under reflux conditions as a reaction with an additional solid reactant, Li₂S. x A mixture of LiX and optional oxygen-containing reactants is formed as a solvated complex of Li3PS4·solvent to form a suspension intermediate, wherein the volume ratio of solvent 1 to solvent 2 is 1-4, preferably 0.5-1.5, and the relative proportions of different reactants are determined according to the chemical formula of the final compound in the form of lithium-sulfur silver-germanium ore particles. 7-(a+b) PS 6-(a+b+c) O c X a Q b Select according to stoichiometry; B) Centrifuge, redisperse the centrifuged phase in a third anhydrous solvent that is the same as or different in properties from the first solvent and the second solvent, and then filter and wash the intermediate; C) Drying, preferably under reduced pressure, at a temperature of 25°C to 150°C for 1 to 10 hours; and D) Heat treatment, at a temperature of 300°C to 600°C for 1 to 10 hours.

2. The method for synthesizing silver-germanium sulfide particles according to claim 1, wherein in step A): A1) React lithium reactants Li2S x Li₂S, preferably Li₂S, halides Liₓ or PSX₃, preferably Liₓ, and optional oxygen-containing halogen reactants are dispersed in a first polar solvent (solvent 1) under stirring, wherein the lithium reactant Li₂S x The mass concentration in the solvent is 10 g / L-100 g / L, preferably 30 g / L-70 g / L; the mass concentration of the halide LiX or PSX3 in the solvent is 1 g / L-100 g / L, preferably 5 g / L-80 g / L; the mass concentration of the oxygen-containing halogen reactant is 0.1 g / L-10 g / L; and the resulting suspension is heated at 25°C to 50°C, preferably 30°C to 40°C. A2) Then, the phosphorus reactant Rp is dispersed in a second polar solvent (solvent 2) under stirring, wherein the mass concentration of the phosphorus reactant in the solvent is 10 g / L-100 g / L, preferably 30 g / L-80 g / L, more preferably 35 g / L-70 g / L, and the resulting suspension is heated at 50°C to 150°C, preferably 90°C to 110°C. A3) A solution of lithium reactants and halides, preferably Li2S and LiX, is gradually added to a suspension of temperature-activated phosphorus reactants, preferably P2S5, over a period of 1 to 6 minutes, preferably 2 to 4 minutes. The resulting suspension is then refluxed under an inert atmosphere and with stirring for 1 to 24 hours, preferably 2 to 8 hours.

3. The method for synthesizing silver-germanium sulfide particles according to claim 1, wherein in step A): A1) The first part of the lithium reactant Li2S x The preferred lithium reactant, Li2S, and the preferred phosphorus reactant, P2S5, are dispersed in a first polar solvent (solvent 1) under stirring. The mass concentration of the lithium reactant, Li2S, in the solvent is preferably 3 g / L-30 g / L, more preferably 5 g / L-20 g / L. The mass concentration of the phosphorus reactant, P2S5, in the solvent is preferably 10 g / L-100 g / L, more preferably 30 g / L-80 g / L, more preferably 35 g / L-70 g / L. The resulting suspension is heated at 25°C to 50°C, preferably 30°C to 40°C, to form a solution. A2) The lithium reactant Li2S from the second part x The lithium reactant Li₂S is dispersed in a second polar solvent (solvent 2) with halides LiX or PSX₃ under stirring. x The mass concentration in the solvent is 10 g / L-80 g / L, preferably 5 g / L-70 g / L, and the mass concentration of the halide LiX or PSX3 is 1 g / L-100 g / L, preferably 5 g / L-80 g / L. The resulting suspension is heated at 50°C to 150°C, preferably 90°C to 110°C. A3) Then, a solution of lithium reactants and phosphorus reactants, preferably Li2S and P2S5, is gradually added to a suspension of lithium reactants and halides, preferably Li2S+LiX, over a period of 1 to 6 minutes, preferably 2 to 4 minutes, and the resulting suspension is refluxed under an inert atmosphere and with stirring for 1 to 24 hours, preferably 2 to 8 hours.

4. The synthesis method according to any one of claims 1 to 3, wherein the intermediate in the form of a solvated complex is recovered as a wet powder by centrifugation at 1000 to 10000 rpm for 5 to 30 minutes, redispersing in an anhydrous solvent, and then washing on glass frit with the same or different anhydrous solvents.

5. The synthesis method according to any one of claims 1 to 4, wherein the drying in step C) is carried out at 10°C. -2 Up to 10 -3 The test was conducted for 2 to 6 hours at a pressure of mbar and a temperature of 40°C to 80°C.

6. The synthesis method according to any one of claims 1 to 5, wherein a heat treatment step D) is performed after drying in step C), said step D) under an inert gas flow or at 10 -2 Up to 10 -3 The process was carried out in a crossflow bed reactor under reduced pressure of mbar.

7. The synthesis method according to claim 6, wherein the inert gas is argon or nitrogen or a mixture of both, and the gas flow rate is 1 L / g / h-15 L / g / h, preferably 8-12 L / h / g.

8. The synthesis method according to any one of the preceding claims, wherein the reactant Li2S is subjected to dry mechanical milling, solution mechanical milling, or dissolution-precipitation in a solvent prior to suspension. x Preprocessing is performed.

9. The synthesis method according to any one of the preceding claims, wherein the polar solvent, whether the first solvent (solvent 1) or the second solvent (solvent 2), is selected from cyclic or linear ethers, esters, nitriles, alcohols and thiols.

10. The synthesis method according to any one of claims 1 to 9, wherein X = Cl, a = 1, b = 0, c = 0, to obtain the silver-sulfur germanium mineral phase Li6PS5Cl.

11. The synthesis method according to any one of claims 1 to 9, wherein X = Cl, a = 1.5, b = 0, c = 0, to obtain the Li-silver-germanium ore phase. 5.5 PS 4.5 Cl 1.5 .

12. The synthesis method according to any one of claims 1 to 9, wherein X = Cl, Q = Br, a = 0.5, b = 0.5, c = 0, yielding a sulfide-silver-germanium mineral phase Li6PS5Cl 0.5 Br 0.5 .

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