A solid electrolyte of argyrodite type and a method for preparing and using the same

Abstract

The application provides a solid electrolyte of argyrodite type and a preparation method and application thereof, and belongs to the technical field of solid electrolytes. The preparation method of the solid electrolyte of argyrodite type comprises the following steps: mixing Li2O, Li2S, LiF, LiX, Sb2O3 and P2S5 according to the stoichiometric ratio of Li6P 1‑z S 5‑x X 1‑y -O x+1.5z F y Sb z to obtain mixed raw materials; the mixed raw materials are added into a ball mill to perform first ball milling to obtain mixed powder; the rotating speed of the ball mill is increased to perform second ball milling to obtain synthesis powder; after the synthesis powder is pressed, the solid electrolyte of argyrodite type is obtained through heat treatment; wherein, 0

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolytes, in particular to an argyrodite-type solid electrolyte, a preparation method therefor and an application thereof. Background Art

[0002] In recent years, with the rapid development of industries such as new energy vehicles, green energy and smart grids, people have put forward increasingly higher requirements for the energy density and safety performance of batteries. Traditional liquid lithium-ion batteries use flammable and explosive organic liquid electrolytes, and the safety problem has become increasingly prominent, which has gradually become a key issue restricting the development of lithium-ion batteries.

[0003] Sulfide solid electrolytes have the advantages of ionic conductivity comparable to that of liquid electrolytes, high mechanical strength, negligible grain boundary effect, and moderate cost. Therefore, they are considered as a potential solution for all-solid-state batteries. However, this electrolyte has low electrode interface compatibility and poor stability in air, and is extremely easy to react with water and oxygen in air, thereby causing deterioration and affecting battery performance. Summary of the Invention

[0004] The object of the present disclosure is to overcome the shortcomings of the prior art and provide an argyrodite-type solid electrolyte, a preparation method therefor and an application thereof.

[0005] To achieve the above object, the technical solution adopted by the present disclosure is:

[0006] In a first aspect, a preparation method of an argyrodite-type solid electrolyte is provided, comprising the following steps:

[0007] Mix Li2O, Li2S, LiF, LiX, Sb2O3 and P2S5 according to Li6P 1-z S 5-x X 1-y -O x+1.5z F y Sb z according to the stoichiometric ratio to obtain a mixed raw material;

[0008] adding the mixed raw material into a ball mill, and performing a first ball milling to obtain mixed powder;

[0009] increasing the rotating speed of the ball mill, and performing a second ball milling to obtain synthetic powder;

[0010] after pressing the synthetic powder, subjecting the same to heat treatment to obtain the argyrodite-type solid electrolyte;

[0011] wherein 0 < x ≤ 1, 0 < y ≤ 0.25, 0 < z ≤ 0.3; and said X is one of Cl, Br and I.

[0012] Secondly, a sulfosilver germanium ore type solid electrolyte is provided, which is prepared by the preparation method of the sulfosilver germanium ore type solid electrolyte, wherein the sulfosilver germanium ore type solid electrolyte includes an electrolyte core layer and a shell layer including LiF and LiO2 covering the electrolyte core layer.

[0013] Thirdly, a solid-state lithium-ion battery is provided, the solid-state lithium-ion battery comprising the aforementioned sulfogermanium ore-type solid electrolyte.

[0014] Compared with the prior art, the beneficial effects of this disclosure are as follows: This invention improves the conductivity, humid air resistance, and electrode interface compatibility of the silver sulfide germanium ore-type solid electrolyte by controlling the doping ratio of F, O, and Sb, staged ball milling, and controlling the cooling rate of heat treatment; Figure 1 As shown, in the argyrogermanium sulfide solid electrolyte, F replaces part of X, O replaces part of S, and Sb replaces part of P in the crystal lattice, forming a multi-element network of P / Sb / F / X / O / S that enhances the stability of the crystal structure. Furthermore, the excess O and F, under a specific cooling rate, accumulate on the surface of the argyrogermanium sulfide solid electrolyte, forming a LiF@Li2O shell. The LiF@Li2O shell has a similar structure to the SEI film, effectively preventing humid air from contacting the internal argyrogermanium sulfide unit cells, while also enhancing the interfacial compatibility between the argyrogermanium sulfide solid electrolyte and the electrode. The staged ball milling process promotes the reactions between the elements, which is beneficial for improving the structural stability of the argyrogermanium sulfide unit cells, thereby improving the overall performance of the argyrogermanium sulfide solid electrolyte. Attached Figure Description

[0015] Figure 1 The diagram shows the structure of the sulfide-silver-germanium ore type solid electrolyte of the present invention (a) and the principle diagram of LiF@Li2O shell layer enhancing electrode interface compatibility (b). Detailed Implementation

[0016] To facilitate understanding of this disclosure, a more complete description will be provided below. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0017] As used in this article:

[0018] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0019] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0020] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1-5” is disclosed, the described range should be interpreted as including ranges “1-4”, “1-3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0021] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0022] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0023] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0024] In a first aspect, a method for preparing a sulfide-germanium ore-type solid electrolyte is provided, comprising the following steps:

[0025] Li₂O, Li₂S, LiF, LiX, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb z The raw materials are mixed in stoichiometric proportions to obtain a mixed raw material;

[0026] adding the mixed raw materials into a ball mill, and performing a first ball milling to obtain mixed powder;

[0027] increasing the rotating speed of the ball mill, and performing a second ball milling to obtain synthetic powder;

[0028] pressing the synthetic powder, and performing heat treatment to obtain the argyrodite-type solid electrolyte;

[0029] wherein 0 < x ≤ 1, 0 < y ≤ 0.25, 0 < z ≤ 0.3; and X is one of Cl, Br and I.

[0030] the present invention improves the ionic conductivity, humid air tolerance and electrode interface compatibility of the argyrodite-type solid electrolyte by controlling the doping ratios of F, O and Sb, adopting staged ball milling and controlling the cooling rate of heat treatment; as Figure 1 shown, in the argyrodite-type solid electrolyte, F element replaces part of X in the crystal lattice, O replaces part of S, and Sb replaces part of P, forming a P / Sb / F / X / O / S multi-component structure network that enhances the stability of the crystal structure; and part of O and F with excess doping concentration are enriched on the surface of the argyrodite-type solid electrolyte at a specific cooling rate to form a LiF@Li₂O shell layer. The LiF@Li₂O shell layer has a similar structure to the SEI film, which can effectively block the contact between humid air and the internal argyrodite-type unit cell, and can also enhance the interface compatibility between the argyrodite-type solid electrolyte and an electrode; the staged ball milling process can promote the reaction between various elements, which is beneficial to improving the structural stability of the argyrodite-type unit cell, thereby improving the overall performance of the argyrodite-type solid electrolyte.

[0031] for example, in different embodiments, x can be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, 1;

[0032] for example, in different embodiments, y can be, but is not limited to, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, 0.2, 0.22, 0.25;

[0033] for example, in different embodiments, z can be, but is not limited to, 0.05, 0.1, 0.13, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3;

[0034] in some embodiments, the heat treatment step comprises: heating to 450-650°C at a heating rate of 1-5°C / min, keeping the temperature, then cooling to room temperature at a cooling rate of 1-5°C / min, wherein the heat preservation time is 6-10h;

[0035] In different embodiments, the temperature of the heat treatment can be, but is not limited to, 450°C, 470°C, 500°C, 520°C, 550°C, 580°C, 600°C, 630°C, or 650°C.

[0036] In different embodiments, the cooling rate of the heat treatment is 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min, 4.5℃ / min, or 5℃ / min.

[0037] In different embodiments, the heating rate of the heat treatment is 1-5℃ / min, for example, but not limited to 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min, 4.5℃ / min, and 5℃ / min.

[0038] In different implementations, the heat treatment time is 6-10 hours, for example, but not limited to 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, and 10 hours.

[0039] In some embodiments, the first ball mill rotates at a speed of 200-400 rpm, and the second ball mill rotates at a speed of 500-650 rpm.

[0040] In different embodiments, the rotational speed of the first ball mill may be, but is not limited to, 200 rpm, 250 rpm, 300 rpm, 350 rpm, or 400 rpm;

[0041] In different embodiments, the rotational speed of the second ball mill may be, but is not limited to, 500 rpm, 520 rpm, 550 rpm, 570 rpm, 600 rpm, 630 rpm, or 650 rpm.

[0042] In some embodiments, the first ball milling time is 1-3 hours, for example, but not limited to 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours.

[0043] In some embodiments, the second ball milling time is 8-10 hours, for example, but not limited to 8 hours, 8.5 hours, 9 hours, 9.5 hours, or 10 hours.

[0044] In some embodiments, the ball-to-material ratio of the first ball mill and the second ball mill is independently 10:1 to 20:1, for example, but not limited to 10:1, 11:1, 13:1, 15:1, 18:1, 20:1.

[0045] Specifically, the grinding balls in the first and second ball mills are zirconium oxide.

[0046] Those skilled in the art can select grinding balls of different diameters for ball milling according to the actual situation. Ball milling with grinding balls of different diameters is beneficial to the process optimization of sulfosilver germanium ore-type solid electrolytes, and realizes the synthesis of sulfosilver germanium ore-type solid electrolytes with low energy consumption and low cost.

[0047] Specifically, the mass ratio of grinding balls of different diameters can be 10mm:5mm:2mm = 1:2:1 or 5mm:2mm:0.5mm = 1:2:1.

[0048] In some embodiments, the Li2O, Li2S, LiF, LiX, Sb2O3 and P2S5 are arranged in a Li6P configuration. 1-z S 5-x X 1-y -O x+1.5z F y Sb z In the step of mixing by stoichiometry, the mixing time is 5-25 min, for example, but not limited to 5 min, 8 min, 10 min, 13 min, 15 min, 17 min, 20 min, 23 min, and 25 min.

[0049] Secondly, a sulfosilver germanium ore type solid electrolyte is provided, which is prepared by the preparation method of the sulfosilver germanium ore type solid electrolyte, wherein the sulfosilver germanium ore type solid electrolyte includes an electrolyte core layer and a shell layer including LiF and LiO2 covering the electrolyte core layer.

[0050] In some embodiments, the electrolyte core layer is composed of P, Sb, F, O, S and halogen X, wherein X is one of Cl, Br and I.

[0051] In some embodiments, the weight retention rate of the sulfogermanium ore-type solid electrolyte is 96%-98% after being exposed to air for 15 minutes; the conductivity retention rate of the sulfogermanium ore-type solid electrolyte is 85%-90% after being exposed to air for 2 hours.

[0052] Thirdly, a solid-state lithium-ion battery is provided, the solid-state lithium-ion battery comprising the aforementioned sulfogermanium ore-type solid electrolyte.

[0053] In some embodiments, the solid-state lithium-ion battery retains 55%-60% of its capacity after 800 charge-discharge cycles, and its capacity decay rate with varying current density is 55%-58%.

[0054] Example 1

[0055] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0056] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x Cl 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0.1, z = 0.1;

[0057] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0058] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 15:1.

[0059] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0060] Example 2

[0061] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0062] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x Cl 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.5, y = 0.15, z = 0.15;

[0063] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0064] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 15:1.

[0065] After the synthetic powder is pressed into a pellet, it is heated to 450°C at a heating rate of 1°C / min, held at 450°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0066] Example 3

[0067] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0068] Li₂O, Li₂S, LiF, LiBr, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x Br 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.5, y = 0.3, z = 0.2;

[0069] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0070] The first ball mill operates at a speed of 200 rpm for 1 hour; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio for both the first and second ball mills is 15:1.

[0071] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0072] Example 4

[0073] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0074] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x Cl 1-y -O x+1.5z F y Sbz Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0.1, z = 0.1;

[0075] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 5mm:2mm:0.5mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0076] The first ball mill operates at a speed of 400 rpm for 3 hours; the second ball mill operates at a speed of 650 rpm for 10 hours; the ball-to-material ratio of the first and second ball mills is 15:1.

[0077] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0078] Example 5

[0079] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0080] Li₂O, Li₂S, LiF, LiI, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x I 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.5, y = 0.15, z = 0.15;

[0081] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0082] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 15:1.

[0083] After the synthetic powder is pressed into a pellet, it is heated to 650°C at a heating rate of 5°C / min, held at 650°C for 8 hours, and cooled to room temperature at a cooling rate of 5°C / min. The resulting product is then ground to obtain the sulfosilver germanite-type solid electrolyte.

[0084] Example 6

[0085] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0086] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x Cl 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 1, y = 0.25, z = 0.3;

[0087] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0088] The first ball mill operates at a speed of 200 rpm for 1 hour; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 15:1.

[0089] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0090] Example 7

[0091] This embodiment provides a method for preparing a sulfide-germanium ore-type solid electrolyte, including the following steps:

[0092] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x Cl 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.3, y = 0.15, z = 0.1;

[0093] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0094] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 15:1.

[0095] After the synthetic powder is pressed into a pellet, it is heated to 550°C at a heating rate of 1°C / min, held at 550°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0096] Comparative Example 1

[0097] This comparative example provides a method for preparing a sulfide-germanium ore-type solid electrolyte, comprising the following steps:

[0098] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0, y = 0, z = 0;

[0099] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0100] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 10:1.

[0101] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0102] Comparative Example 2

[0103] This comparative example provides a method for preparing a sulfide-germanium ore-type solid electrolyte, comprising the following steps:

[0104] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb zWeigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0, z = 0;

[0105] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0106] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 10:1.

[0107] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0108] Comparative Example 3

[0109] This comparative example provides a method for preparing a sulfide-germanium ore-type solid electrolyte, comprising the following steps:

[0110] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0.1, z = 0;

[0111] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0112] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 10:1.

[0113] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0114] Comparative Example 4

[0115] This comparative example provides a method for preparing a sulfide-germanium ore-type solid electrolyte, comprising the following steps:

[0116] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0, z = 0.1;

[0117] The mixed raw materials are added to a planetary ball mill, and the first ball milling is performed using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain a mixed powder; the speed of the ball mill is increased to perform a second ball milling to obtain a synthetic powder.

[0118] The first ball mill operates at a speed of 200 rpm for 2 hours; the second ball mill operates at a speed of 500 rpm for 8 hours; the ball-to-material ratio of the first and second ball mills is 10:1.

[0119] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0120] Comparative Example 5

[0121] This comparative example provides a method for preparing a sulfosilver germanite-type solid electrolyte, which differs from the method for preparing the sulfosilver germanite-type solid electrolyte in Example 1 only in that the cooling rate is 7°C / min.

[0122] Comparative Example 6

[0123] This comparative example provides a method for preparing a sulfide-germanium ore-type solid electrolyte, comprising the following steps:

[0124] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0.1, z = 0.1;

[0125] The mixed raw materials were added to a planetary ball mill and ball milled using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain the synthetic powder.

[0126] The ball mill operates at a speed of 200 rpm for 10 hours, with a ball-to-material ratio of 10:1.

[0127] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0128] Comparative Example 7

[0129] This comparative example provides a method for preparing a sulfide-germanium ore-type solid electrolyte, comprising the following steps:

[0130] Li₂O, Li₂S, LiF, LiCl, Sb₂O₃, and P₂S₅ were arranged according to Li₆P 1-z S 5-x X 1-y -O x+1.5z F y Sb z Weigh the ingredients according to their stoichiometric ratio, grind them in a mortar for 15 minutes to obtain a mixed raw material; where x = 0.25, y = 0.1, z = 0.1;

[0131] The mixed raw materials were added to a planetary ball mill and ball milled using zirconium oxide grinding balls with a diameter ratio of 10mm:5mm:2mm = 1:2:1 to obtain the synthetic powder.

[0132] The ball mill operates at a speed of 500 rpm for 10 hours, with a ball-to-material ratio of 10:1.

[0133] After the synthetic powder is pressed into a pellet, it is heated to 530°C at a heating rate of 1°C / min, held at 530°C for 8 hours, and cooled to room temperature at a cooling rate of 1°C / min. The resulting product is then ground to obtain the sulfosilver germanium ore type solid electrolyte.

[0134] Performance testing

[0135] The performance of the silver-germanium sulfide-type solid electrolytes obtained in the test examples and comparative examples was tested using the following methods:

[0136] (1) Conductivity: The sulfide-germanium ore type solid electrolyte powder was placed in a polyether ether ketone (PEEK) mold and cold-pressed into a sheet with a thickness of 1 mm and a diameter of 10 mm under a pressure of 200 MPa (surface pressure of the electrolyte sheet); two stainless steel rods with a diameter of 10 mm were clamped on both sides of the sample as current collectors; the impedance analyzer was used to test the electrolyte under the conditions of 25℃, 50 mV AC voltage amplitude, and 1 Hz-1 MHz frequency range. The resistance R of the electrolyte was obtained by fitting the Nyquist plot, and the conductivity was calculated according to the formula σ=L / R·A, where L is the sample thickness and A is the sample area;

[0137] (2) H2S yield: Weigh 50 mg of sulfosilver germanium ore type solid electrolyte powder and place it in a sealed container with an air humidity of 60% RH. After 2 hours, weigh the remaining weight of the sulfosilver germanium ore type solid electrolyte powder. The difference between the weight and the initial weight is the H2S yield.

[0138] (3) Capacitance retention: The polyetheretherketone (PEEK) mold containing argyrocyanide-type solid electrolyte powder was subjected to a current density of 0.1-2 mA·cm⁻¹. -2 Under conditions of 2.5-4V and 25℃, charge-discharge cycles are performed. According to the formula, capacitance retention rate = C N The capacitance retention rate is calculated by / C0×*100, where C0 is the initial discharge capacity, C N This represents the discharge capacity after N cycles.

[0139] (4) Capacitance decay rate: The capacitance decay rate is given by the formula: Capacitance decay rate = C 0.1 -C2 / C 0.1 Calculate by multiplying by 100%, where C 0.1 For a current density of 0.1 mA·cm -2 The capacitance at that time, C2 is the current density of 2mA·cm -2 The electrical capacity at that time.

[0140] The test results are shown in Table 1-4.

[0141] Table 1

[0142]

[0143] Table 2

[0144] sample weight / g Post-exposure weight / g Weight retention rate <![CDATA[H₂S yield]]> Example 1 2.070 2.008 97％ 3％ Example 2 2.151 2.108 98％ 2％ Example 3 2.057 1.995 97％ 3％ Example 4 2.134 2.049 96％ 4％ Example 5 2.271 2.203 97％ 3％ Example 6 2.147 2.104 98％ 2％ Example 7 2.370 2.299 97％ 3％ Comparative Example 1 2.067 1.736 84％ 16％ Comparative Example 2 2.317 2.062 89％ 11％ Comparative Example 3 2.184 1.791 82％ 8％ Comparative Example 4 2.273 1.834 81％ 19％ Comparative Example 5 2.352 1.483 64％ 36％ Comparative Example 6 2.061 1.608 78％ 22％ Comparative Example 7 2.183 1.763 81％ 19％

[0145] Table 3

[0146]

[0147]

[0148] Table 4

[0149]

[0150] As shown in Tables 1-4, the conductivity retention rate of the sulfosilver germanium ore-type solid electrolyte of the present invention is ≥85% after exposure to a closed container with an air humidity of 60% RH for 2 hours, and the H2S yield is ≤5% after exposure to a closed container with an air humidity of 60% RH for 15 minutes. The capacity retention rate of the battery containing the sulfosilver germanium ore-type solid electrolyte of the present invention is 55%-60% after 800 charge-discharge cycles, and the capacity decay rate is 55%-58%, indicating that the sulfosilver germanium ore-type solid electrolyte of the present invention has high air stability and electrical performance.

[0151] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of this disclosure and not to limit the scope of protection of this disclosure. Although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this disclosure without departing from the substance and scope of the technical solutions of this disclosure.

Claims

1. A method for preparing a sulfide-germanium ore-type solid electrolyte, characterized in that, comprising the following steps: Li2O, Li2S, LiF, LiX, Sb2O3, and P2S5 are mixed at a stoichiometric ratio of Li6P 1-z S 5-x X 1-y -O x+1.5z F y Sb z to obtain a mixed raw material; adding the mixed raw materials into a ball mill, and carrying out first ball milling to obtain mixed powder; increasing the rotating speed of the ball mill, and carrying out second ball milling to obtain synthetic powder; pressing the synthetic powder, and then performing heat treatment to obtain the argyrodite-type solid electrolyte; wherein 0 < x ≤ 1, 0 < y ≤ 0.25, 0 < z ≤ 0.3; and X is one of Cl, Br and I.

2. The method for preparing the sulfide-germanium ore-type solid electrolyte as described in claim 1, characterized in that, the heat treatment step comprises: heating to 450-650°C at a heating rate of 1-5°C / min, keeping the temperature, then cooling to room temperature at a cooling rate of 1-5°C / min, wherein the holding time is 6-10 h.

3. The method for preparing the sulfide-germanium ore-type solid electrolyte as described in claim 1, characterized in that, the time of the first ball milling is 1-3 h; and / or, the rotating speed of the ball mill for the first ball milling is 200-400 rpm; and / or, the time of the second ball milling is 8-10 h; and / or, the rotating speed of the ball mill for the second ball milling is 500-650 rpm.

4. The method for preparing the sulfide-germanium ore-type solid electrolyte as described in claim 1, characterized in that, the ball-to-material ratio of the first ball milling is 10:1-20:1; and / or, the ball-to-material ratio of the second ball milling is 10:1-20:

1.

5. The method for preparing the sulfide-germanium ore-type solid electrolyte as described in claim 1, characterized in that, The process involves mixing Li₂O, Li₂S, LiF, LiX, Sb₂O₃, and P₂S₅ according to Li₆P. 1-z S 5-x X 1-y -O x+1.5z F y Sb z In the step of mixing by stoichiometry, the mixing time is 5-25 minutes.

6. A sulfide-germanium ore type solid electrolyte, characterized in that, prepared by the preparation method of the argyrodite-type solid electrolyte according to any one of claims 1-5, wherein the argyrodite-type solid electrolyte comprises an electrolyte core layer and a shell layer comprising LiF and LiO₂ that coats the electrolyte core layer.

7. The sulfide-germanium ore type solid electrolyte as described in claim 6, characterized in that, the electrolyte core layer consists of P, Sb, F, O, S and halogen X, wherein X is one of Cl, Br and I.

8. The sulfide-germanium ore type solid electrolyte as described in claim 6, characterized in that, the weight retention rate of the argyrodite-type solid electrolyte after being exposed to air for 15 minutes is 96%-98%; and the conductivity retention rate of the argyrodite-type solid electrolyte after being exposed to air for 2 hours is 85%-90%.

9. A solid-state lithium-ion battery, characterized in that, the solid-state lithium-ion battery comprises the argyrodite-type solid electrolyte according to claim 6.

10. The solid-state lithium-ion battery as described in claim 9, characterized in that, the capacity retention rate of the solid-state lithium-ion battery after 800 charge-discharge cycles is 55%-60%, and the capacity attenuation rate of the solid-state lithium-ion battery along with the change of current density is 55%-58%.

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