Fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability as well as preparation method and application of fluorine-doped sulfide solid electrolyte

Abstract

The invention belongs to the technical field of solid electrolytes, and relates to a fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability, and a preparation method and application thereof. The fluorine-doped sulfide solid electrolyte has a chemical formula as shown in a formula I or a formula II: Li < 10-2x > Ge < 1-x > Sn < x > P2S < 12-2x > F < 2x > formula I, and x is more than 0 and less than 1; li < 6 + / -3y > P < 1-y > Sn < y > S5Cl < 1-2y > F < 2y > formula II, and y is more than 0 and less than 1. A fluorine source for preparing the fluorine-doped sulfide solid electrolyte is SnF2. According to the sulfide solid electrolyte and the preparation method thereof, SnF2 is taken as a fluorine source, fluorine is introduced, the prepared sulfide solid electrolyte has wet air stability and lithium metal stability while high ionic conductivity is guaranteed, and an assembled all-solid-state battery shows excellent cycling stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid electrolytes and relates to a fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability, a preparation method and an application thereof. Background Art

[0002] As a key component of modern energy technology, lithium-ion batteries, with their high energy density and long cycle life, have shown broad application prospects in portable electronic devices, electric / hybrid vehicles, and large-scale stationary energy storage systems. However, commercial lithium-ion batteries currently utilize organic electrolytes as the charge transport medium. While these electrolytes offer excellent ionic conductivity, they suffer from poor thermal stability, low flash points, and potential leakage. In the event of abnormal conditions such as overcharging or local short circuits, the battery can experience thermal runaway, spontaneous combustion, or even explosion, posing a significant safety hazard. Furthermore, the organic hosts in the liquid electrolyte readily react with the active lithium metal anode, significantly reducing battery capacity and cycle life. This issue is particularly prominent in the development of high-energy-density batteries, as higher energy density often requires higher active material loadings and faster charge and discharge rates. This exacerbates side reactions between the lithium metal anode and the electrolyte, limiting the development of liquid electrolyte-based lithium-ion batteries towards higher energy densities.

[0003] Inorganic solid electrolytes offer advantages such as enhanced thermal stability, a wider potential window, and non-flammability and non-volatility, making them suitable for all-solid-state lithium batteries assembled with lithium metal anodes, demonstrating high safety and energy density. Among inorganic solid electrolytes, sulfide solid electrolytes have attracted considerable attention due to their high ionic conductivity and excellent machinability. However, sulfide solid electrolytes are sensitive to moisture and decompose upon contact with water to produce toxic H2S gas, which significantly decreases ionic conductivity and poses significant challenges for storage, transportation, and use. Furthermore, sulfide solid electrolytes are thermodynamically unstable with metallic lithium. During battery cycling, they spontaneously form mixed ionic and electronic conductors, triggering local reactions and structural degradation within the electrolyte, leading to the formation of high interfacial resistance phases and lithium dendrites. This cycle, in turn, ultimately leads to battery failure due to short circuits or short-circuit failure. The energy density, cycling stability, and safety of all-solid-state batteries depend heavily on the compatibility of the sulfide solid electrolyte with lithium metal. Summary of the Invention

[0004] The present invention addresses the shortcomings of existing sulfide solid electrolytes and provides a fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability, as well as its preparation method and application. The fluorine-doped sulfide solid electrolyte maintains high ionic conductivity while also being stable to humid air and lithium metal. The assembled all-solid-state battery exhibits excellent cycling stability and rate performance.

[0005] One object of the present invention is achieved by the following technical solutions:

[0006] A fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability has a chemical formula as shown in Formula I or Formula II:

[0007] Li 10-2x Ge 1-x Sn x P2S 12-2x F 2x Formula I,

[0008] Among them, 0<x<1;

[0009] Li 6±3y P 1-y Sn y S5Cl 1-2y F 2y Formula II,

[0010] Among them, 0<y<1.

[0011] Preferably, in Formula I, 0 < x ≤ 0.1, for example, x can be any one of 0.001, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.1; in Formula II, 0 < y ≤ 0.1, for example, y can be any one of 0.001, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.1. Under the above parameters, the sulfide solid electrolyte has high ionic conductivity and better stability to humid air and lithium metal.

[0012] Preferably, the raw materials for preparing the fluorine-doped sulfide solid electrolyte of the chemical formula shown in Formula I include: a lithium source, a germanium source, a phosphorus source and a fluorine source; the fluorine source is SnF2.

[0013] Preferably, the raw materials for preparing the fluorine-doped sulfide solid electrolyte of the chemical formula shown in Formula II include: a lithium source, a phosphorus source, a chlorine source and a fluorine source; the fluorine source is SnF2.

[0014] Preferably, the lithium source is lithium sulfide, which refers to a compound containing two elements, sulfur and lithium. More preferably, the lithium source is Li2S.

[0015] Preferably, the germanium source is germanium sulfide, which refers to a compound containing two elements, sulfur and germanium. Further preferably, the germanium source is GeS2.

[0016] Preferably, the phosphorus source is a phosphorus sulfide, such as phosphorus trisulfide (P2S3) and phosphorus pentasulfide (P2S5). These phosphorus sulfides can be used alone or in combination of two or more. More preferably, the phosphorus source is P2S5.

[0017] Preferably, the chlorine source is lithium chloride.

[0018] Preferably, the fluorine-doped sulfide solid electrolyte of the chemical formula represented by Formula I has an ionic conductivity of ≥4.0 mS / cm at 25° C., and the fluorine-doped sulfide solid electrolyte of the chemical formula represented by Formula II has an ionic conductivity of ≥2.0 mS / cm at 25° C.

[0019] Further preferably, the fluorine-doped sulfide solid electrolyte of the chemical formula represented by Formula I has an ionic conductivity of 5.0 to 10.0 mS / cm at 25°C, and the fluorine-doped sulfide solid electrolyte of the chemical formula represented by Formula II has an ionic conductivity of 2.5 to 8.0 mS / cm at 25°C.

[0020] Preferably, the fluorine-doped sulfide solid electrolyte of the chemical formula I is exposed to air at 35-40% relative humidity for 120 min at 25°C, and the total amount of hydrogen sulfide released is ≤1.0 cm 3 / g, ionic conductivity retention rate ≥15%; the fluorine-doped sulfide solid electrolyte of the chemical formula shown in Formula II is exposed to air at 35-40% relative humidity at 25°C for 10 minutes, and the total amount of hydrogen sulfide released is ≤1.5cm 3 / g, ion conductivity retention rate ≥10%.

[0021] Further preferably, the fluorine-doped sulfide solid electrolyte of the chemical formula I is exposed to air at 35-40% relative humidity at 25°C for 120 minutes, and the total amount of hydrogen sulfide released is 0.01-0.5 cm 3 / g, the ionic conductivity retention rate is 15-70%; the fluorine-doped sulfide solid electrolyte of the chemical formula shown in formula II is exposed to air at 35-40% relative humidity at 25°C for 10 minutes, and the total amount of hydrogen sulfide released is 0.01-1.0 cm 3 / g, and the ion conductivity retention rate is 10-50%.

[0022] The second object of the present invention is achieved through the following technical solutions:

[0023] A method for preparing a fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability comprises the following steps:

[0024] Weighing a lithium source, a germanium source, a phosphorus source, and a fluorine source in a stoichiometric ratio according to Formula I, or weighing a lithium source, a phosphorus source, a chlorine source, and a fluorine source in a stoichiometric ratio according to Formula II, and mechanically mixing them to obtain a precursor powder;

[0025] The precursor powder is subjected to high-temperature calcination treatment and then cooled to room temperature to obtain the fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability.

[0026] Preferably, the mechanical mixing comprises one or more of high-energy ball milling, mechanical stirring, mechanical shaking, and roller milling, and the mixing time is 0.1 to 48 hours. More preferably, the mixing time is 1 to 40 hours, for example, any one of 1 hour, 2 hours, 5 hours, 8 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, and 40 hours.

[0027] Preferably, the conditions for high-temperature calcination treatment include: under an inert atmosphere, a calcination temperature of 500-700°C, and a calcination time of 0.1-24 hours, for example, it can be any one of 0.1 hour, 0.5 hour, 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 20 hours, 22 hours, and 24 hours.

[0028] The inert atmosphere is one or more of nitrogen and argon.

[0029] Preferably, after high-temperature calcination treatment, the mixture is naturally cooled to room temperature and then ground to obtain the final fluorine-doped sulfide solid electrolyte.

[0030] The third object of the present invention is achieved through the following technical solutions:

[0031] An all-solid-state lithium secondary battery comprises a positive electrode, a negative electrode and the fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention selects SnF2 as a fluorine source, which can introduce the highly electronegative F element into the sulfide solid electrolyte system; through the introduction of the fluorine element, on the one hand, the hydrophilicity of the surface of the solid electrolyte material is reduced by regulating electrons, thereby alleviating the hydrolysis of the sulfide solid electrolyte in humid air; on the other hand, by promoting the formation of lithium vacancies in the solid electrolyte, the diffusion flux of lithium ions in the solid electrolyte is enhanced, thereby preventing lithium ions from being reduced to dendrites; and thus a sulfide solid electrolyte that is stable to humid air and lithium metal is prepared.

[0034] (2) The fluorine-doped sulfide solid electrolyte prepared by the present invention has a high ionic conductivity, which can be as high as 6.28 mS cm -1 ; and the fluorine-doped sulfide solid electrolyte of the present invention has excellent wet air stability and lithium metal compatibility.

[0035] (3) The lithium / lithium symmetric battery assembled using the sulfide solid electrolyte provided by the present invention exhibits excellent cycling stability. Furthermore, the all-solid-state battery assembled using the fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability exhibits excellent cycling stability.

[0036] (4) The preparation method of the fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability provided by the present invention is simple to operate, highly practical, and convenient for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.01 Transmission electron microscopy images and line scanning elemental distribution maps of sulfide solid electrolytes;

[0038] Figure 2 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.01 Sulfide solid electrolyte and Li in Comparative Example 1 10 GeP2S 12 AC impedance spectroscopy of sulfide solid electrolyte;

[0039] Figure 3 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.01 Sulfide solid electrolyte and Li in Comparative Example 110 GeP2S 12 The amount of hydrogen sulfide gas released when the sulfide solid electrolyte is exposed to air with a relative humidity of 38%;

[0040] Figure 4 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.01 Sulfide solid electrolyte and Li in Comparative Example 1 10 GeP2S 12 AC impedance spectroscopy of the sulfide solid electrolyte before and after exposure to air at 38% relative humidity for 20 minutes;

[0041] Figure 5 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.01 Sulfide solid electrolyte and Li in Comparative Example 1 10 GeP2S 12 Cycling curve of lithium / / lithium symmetric battery with sulfide solid electrolyte;

[0042] Figure 6 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.01 Sulfide solid electrolyte and Li in Comparative Example 1 10 GeP2S 12 Long-cycle diagram of all-solid-state batteries with sulfide solid electrolytes. DETAILED DESCRIPTION

[0043] Below by specific embodiment and accompanying drawing, technical scheme of the present invention is further described explanation, it should be understood that specific embodiment described herein is only for helping to understand the present invention, is not used for specific limitation of the present invention.And accompanying drawing used herein, is only for better illustrating the disclosure of the present invention, does not have limiting effect on protection scope.If no special instructions, the raw materials adopted in the embodiment of the present invention are all raw materials commonly used in this area, and the method adopted in the embodiment is all conventional method in this area.

[0044] Example 1

[0045] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0046] Li2S, GeS2, P2S5, and SnF2 (about 1 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas). The ball-to-material ratio was 20:1 and the rotation speed was 600 rpm. After 12 hours of ball milling, Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Precursor powder;

[0047] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Sulfide solid electrolyte.

[0048] Figure 1 Li prepared in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Transmission electron microscope image and line scanning element distribution map of sulfide solid electrolyte. From the line scanning element distribution map, it can be seen that fluorine is evenly distributed in Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 sulfide solid electrolyte.

[0049] Measure output 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 The ionic conductivity of the sulfide solid electrolyte at 25°C is 6.28 mS cm -1 , is Li in Comparative Example 1 10 GeP2S 12 102% of the ionic conductivity of sulfide solid electrolytes (see Figure 2 In addition, after being exposed to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released was 0.21 cm 3 g -1 (See Figure 3 ), and its ion conductivity retention rate is 41%, which is higher than that of Li after exposure to air in Comparative Example 1. 10 GeP2S 12 The ionic conductivity of sulfide solid electrolytes is nearly one order of magnitude higher (see Figure 4 ).

[0050] The Li in the above embodiment 1 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.1 mA cm -2 The lithium symmetric battery can cycle stably for 900 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 positive electrode, and metallic lithium negative electrode were assembled into an all-solid-state battery. The battery was electrochemically tested using a Blue Power CT2001A battery test system. The charge and discharge voltage range was 3.0-4.2V, and the rate was 1C. Constant-rate charge and discharge was performed, and the capacity retention rate after 600 cycles was 80.1%.

[0051] Example 2

[0052] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0053] Li2S, GeS2, P2S5, and SnF2 (about 1 mol%) were weighed in a stoichiometric ratio and placed in a stirrer for mechanical stirring (the atmosphere of the stirrer was argon) at a stirring speed of 500 r / min. After stirring for 12 hours, Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Precursor powder;

[0054] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Sulfide solid electrolyte.

[0055] Measure output 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 The ionic conductivity of the sulfide solid electrolyte at 25°C is 6.19 mS cm -1 , compared with Li in Comparative Example 1 10 GeP2S 12The ionic conductivity of the sulfide solid electrolyte is similar. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.21 cm 3 g -1 , and the ionic conductivity retention rate was 36%.

[0056] The Li in the above Example 2 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.2 mA cm -2 , the lithium symmetric battery can be stably cycled for 700 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 2.5 to 4.3V. After 700 cycles, the capacity retention rate was 84.8%.

[0057] Example 3

[0058] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0059] Li2S, GeS2, P2S5, and SnF2 (about 1 mol%) were weighed according to the stoichiometric ratio and placed in a roller mill for mechanical roller milling (the atmosphere of the roller mill was argon gas), with a ball-to-material ratio of 5:1 and a rotation speed of 200 rpm. After 24 hours, Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Precursor powder;

[0060] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Sulfide solid electrolyte.

[0061] Measure output 9.98 Ge 0.99 Sn 0.01 P2S11.98 F 0.02 The ionic conductivity of the sulfide solid electrolyte at 25°C is 6.21 mS cm -1 , compared with Li in Comparative Example 1 10 Ge0P2S 12 The ionic conductivity of the sulfide solid electrolyte is similar. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.21 cm 3 g -1 , and the ionic conductivity retention rate was 38%.

[0062] The Li in the above Example 3 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.5 mA cm -2 , the lithium symmetric battery can be stably cycled for 550 hours at room temperature. In addition, the sulfide solid electrolyte, LiNi 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 2.5 to 4.3V. After 600 cycles, the capacity retention rate was 79.8%.

[0063] Example 4

[0064] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0065] Li2S, GeS2, P2S5, and SnF2 (about 3 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas). The ball-to-material ratio was 20:1 and the rotation speed was 600 rpm. After 12 hours of ball milling, Li 9.94 Ge 0.97 Sn 0.03 P2S 11.94 F 0.06 Precursor powder;

[0066] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.94 Ge 0.97 Sn 0.03 P2S11.94 F 0.06 Sulfide solid electrolyte.

[0067] Measure output 9.94 Ge 0.97 Sn 0.03 P2S 11.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 5.98 mS cm -1 , compared with Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is similar. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.20 cm 3 g -1 , and the ionic conductivity retention rate was 42%.

[0068] The Li in the above embodiment 4 9.94 Ge 0.97 Sn 0.03 P2S 11.94 F 0.06 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.1 mA cm -2 The lithium symmetric battery can cycle stably for 1000 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 positive electrode, and metallic lithium negative electrode are assembled into an all-solid-state battery. The battery was electrochemically tested using a Blue Power CT2001A battery test system. The charge and discharge voltage range was 3.0-4.2V, and the rate was 1C. Constant-rate charge and discharge was performed, and the capacity retention rate was 76.7% after 800 cycles.

[0069] Example 5

[0070] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0071] Li2S, GeS2, P2S5, and SnF2 (about 5 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas). The ball-to-material ratio was 20:1 and the rotation speed was 600 rpm. After 12 hours of ball milling, Li 9.90 Ge 0.95 Sn 0.05 P2S 11.90 F 0.10 Precursor powder;

[0072] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.90 Ge 0.95 Sn 0.05 P2S 11.90 F 0.10 Sulfide solid electrolyte.

[0073] Measure output 9.90 Ge 0.95 Sn 0.05 P2S 11.90 F 0.10 The ionic conductivity of the sulfide solid electrolyte at 25°C is 5.86 mS cm -1 , compared with Li in Comparative Example 1 10 GeP2S 12 The sulfide solid electrolyte has a similar ionic conductivity. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released was 0.18 cm³ g-1, and the ionic conductivity retention rate was 45%.

[0074] The Li in the above embodiment 5 9.90 Ge 0.95 Sn 0.05 P2S 11.90 F 0.10 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.1 mA cm -2 The lithium symmetric battery can cycle stably for 1200 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 positive electrode, and metallic lithium negative electrode are assembled into an all-solid-state battery. The battery was electrochemically tested using a Blue Power CT2001A battery test system. The charge and discharge voltage range was 3.0-4.2V, and the rate was 1C. Constant-rate charge and discharge was performed, and the capacity retention rate was 81.2% after 800 cycles.

[0075] Example 6

[0076] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0077] Li2S, GeS2, P2S5, and SnF2 (about 8 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas). The ball-to-material ratio was 20:1 and the rotation speed was 600 rpm. After 12 hours of ball milling, Li 9.84 Ge 0.92 Sn 0.08 P2S 11.84 F0.16 Precursor powder;

[0078] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.84 Ge 0.92 Sn 0.08 P2S 11.84 F 0.16 Sulfide solid electrolyte.

[0079] Measure output 9.84 Ge 0.92 Sn 0.08 P2S 11.84 F 0.16 The ionic conductivity of the sulfide solid electrolyte at 25°C is 5.63 mS cm -1 , compared with Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is similar. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.17 cm3 g -1 , and the ionic conductivity retention rate was 47%.

[0080] Li in the above Example 6 9.84 Ge 0.92 Sn 0.08 P2S 11.84 F 0.16 Lithium sheets were attached to each side of the sulfide solid electrolyte, and the assembled lithium / lithium symmetrical battery was cycled using a BlueDian CT2001A battery test system. The current density was 0.1mAcm-2, and the lithium symmetrical battery could cycle stably for 1500 hours at room temperature. In addition, the sulfide solid electrolyte, LiCoO2 positive electrode and metallic lithium negative electrode were assembled into an all-solid-state battery. The battery was electrochemically tested using a BlueDian CT2001A battery test system. The charge and discharge voltage range was 3.0-4.2V, the rate was 1C, and constant rate charge and discharge were performed. After 1000 cycles, the capacity retention rate was 80.3%.

[0081] Example 7

[0082] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0083] Li2S, P2S5, LiCl, and SnF2 (about 1 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas). The ball-to-material ratio was 20:1 and the rotation speed was 600 rpm. After 12 hours of ball milling, Li 6.03 P0.99 Sn 0.01 S5Cl 0.98 F 0.02 Precursor powder;

[0084] The precursor powder was calcined in a muffle furnace at a heating rate of 5°C / min to 580°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 6.03 P 0.99 Sn 0.01 S5Cl 0.98 F 0.02 Sulfide solid electrolyte.

[0085] Measure output 6.03 P 0.99 Sn 0.01 S5Cl 0.98 F 0.02 The ionic conductivity of the sulfide solid electrolyte at 25°C is 3.60 mS cm -1 , which is 112% of the ionic conductivity of the Li6PS5Cl sulfide solid electrolyte in Comparative Example 2. In addition, after exposure to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 0.42 cm 3 g -1 , and the ionic conductivity retention rate was 35%.

[0086] Li in the above Example 7 6.03 P 0.99 Sn 0.01 S5Cl 0.98 F 0.02 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 , the lithium symmetric battery can be stably cycled for 3000 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 500 cycles, the capacity retention rate was 90.4%.

[0087] Example 8

[0088] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0089] Li2S, P2S5, LiCl, and SnF2 (about 2 mol%) were weighed according to the stoichiometric ratio and placed in a roller mill for mechanical roller milling (the atmosphere in the roller mill was vacuum or argon), with a ball-to-material ratio of 5:1 and a rotation speed of 200 rpm. After roller milling for 24 hours, Li 6.06 P 0.98 Sn 0.02 S5Cl 0.96 F 0.04 Precursor powder;

[0090] The precursor powder was calcined in a muffle furnace at a heating rate of 5°C / min to 580°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 6.06 P 0.98 Sn 0.02 S5Cl 0.96 F 0.04 Sulfide solid electrolyte.

[0091] Measure output 6.06 P 0.98 Sn 0.02 S5Cl 0.96 F 0.04 The ionic conductivity of the sulfide solid electrolyte at 25°C is 3.45 mS cm -1 , which is 108% of the ionic conductivity of the Li6PS5Cl sulfide solid electrolyte in Comparative Example 2. In addition, after exposure to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 0.40 cm 3 g -1 , and the ionic conductivity retention rate was 41%.

[0092] Li in the above Example 8 6.06 P 0.98 Sn 0.02 S5Cl 0.96 F 0.04 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. Cycling tests were performed using a BlueDian CT2001A battery test system at a current density of 0.3 mA cm -2 , the lithium symmetric battery can be stably cycled for 1500 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 1,000 cycles, the capacity retention rate was 86.9%.

[0093] Example 9

[0094] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0095] Li2S, P2S5, LiCl, and SnF2 (about 3 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas). The ball-to-material ratio was 20:1 and the rotation speed was 600 rpm. After 12 hours of ball milling, Li 6.09 P 0.97 Sn 0.03 S5Cl 0.94 F 0.06 Precursor powder;

[0096] The precursor powder was calcined in a muffle furnace at a heating rate of 5°C / min to 580°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 6.09 P 0.97 Sn 0.03 S5Cl 0.94 F 0.06 Sulfide solid electrolyte.

[0097] Measure output 6.09 P 0.97 Sn 0.03 S5Cl 0.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 3.37 mS cm -1 , which is 105% of the ionic conductivity of the Li6PS5Cl sulfide solid electrolyte in Comparative Example 2. In addition, after exposure to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 0.41 cm 3 g -1 , and the ionic conductivity retention rate was 42%.

[0098] The Li in the above Example 9 6.09 P 0.97 Sn 0.03 S5Cl 0.94 F 0.06 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 , the lithium symmetric battery can be stably cycled for 3200 hours at room temperature. 0.8 Co 0.1 Mn 0.1An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 1,000 cycles, the capacity retention rate was 82.7%.

[0099] Example 10

[0100] The fluorine-doped sulfide solid electrolyte of this embodiment is prepared by the following steps:

[0101] Li2S, P2S5, LiCl, and SnF2 (about 5 mol%) were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was vacuum or argon) with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After 12 hours of ball milling, Li 6.15 P 0.95 Sn 0.05 S5Cl 0.90 F 0.10 Precursor powder;

[0102] The precursor powder was calcined in a muffle furnace at a heating rate of 5°C / min to 580°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 6.15 P 0.95 Sn 0.05 S5Cl 0.90 F 0.10 Sulfide solid electrolyte.

[0103] Measure output 6.15 P 0.95 Sn 0.05 S5Cl 0.90 F 0.10 The ionic conductivity of the sulfide solid electrolyte at 25°C is 3.14 mS cm -1 , which is similar to the ionic conductivity of the Li6PS5Cl sulfide solid electrolyte in Comparative Example 2. In addition, after exposure to wet air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 0.39 cm 3 g -1 , and the ionic conductivity retention rate was 43%.

[0104] The Li in the above embodiment 10 6.15 P 0.95 Sn 0.05 S5Cl 0.90 F 0.10 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.1 mA cm-2 , the lithium symmetric battery can be stably cycled for 3600 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 1,000 cycles, the capacity retention rate was 84.6%.

[0105] Comparative Example 1

[0106] The preparation method of the sulfide solid electrolyte of Comparative Example 1 is as follows:

[0107] Li2S, GeS2, and P2S5 were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon gas) with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After 12 hours of ball milling, Li 10 GeP2S 12 Precursor powder;

[0108] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 10 GeP2S 12 Sulfide solid electrolyte.

[0109] Measure output 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte at 25°C is 6.15 mS cm -1 In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released was 0.56 cm 3 g -1 , and its ion conductivity retention rate is less than 5%. 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 The comparison of hydrogen sulfide release and conductivity change of sulfide solid electrolyte in air is shown in Figure 1 and Figure 2 , it can be seen that the fluorine-doped sulfide solid electrolyte Li with high ionic conductivity and stability 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02It is more stable in humid air, not easily hydrolyzed to generate toxic H2S, and has a high ion conductivity retention rate.

[0110] The Li in the above Comparative Example 1 10 GeP2S 12 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 The lithium symmetric battery can be stably cycled for 350 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 positive electrode, and metallic lithium negative electrode were assembled into an all-solid-state battery. The battery was electrochemically tested using a Blue Power CT2001A battery test system. The charge and discharge voltage range was 3.0-4.2V, and the rate was 1C. Constant-rate charge and discharge was performed, and the capacity retention rate after 100 cycles was 0.5%.

[0111] Figure 5 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Sulfide solid electrolyte and Li in Comparative Example 1 10 GeP2S 12 Cycling curve of lithium / / lithium symmetric battery with sulfide solid electrolyte, Figure 6 Li in Example 1 of the present invention 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Sulfide solid electrolyte and Li in Comparative Example 1 10 GeP2S 12 Long cycle diagram of all-solid-state battery with sulfide solid electrolyte, from Figure 5 and Figure 6 It is known that the fluorine-doped sulfide solid electrolyte Li 9.98 Ge 0.99 Sn 0.01 P2S 11.98 F 0.02 Compared with Li 10 GeP2S 12 Sulfide solid electrolytes have better stability towards lithium, and the prepared all-solid-state batteries have better cycle stability.

[0112] Comparative Example 2

[0113] The preparation method of the sulfide solid electrolyte of Comparative Example 2 is as follows:

[0114] Li2S, P2S5 and LiCl were weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill was argon) with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li6PS5Cl precursor powder was obtained;

[0115] The precursor powder was calcined in a muffle furnace at a heating rate of 5°C / min to 580°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground uniformly to obtain Li6PS5Cl sulfide solid electrolyte.

[0116] The ionic conductivity of Li6PS5Cl sulfide solid electrolyte was measured to be 3.20 mS cm at 25 °C. -1 In addition, after being exposed to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released reached 1.90 cm 3 g -1 , and its ionic conductivity retention rate is less than 1%.

[0117] The lithium / / lithium symmetrical battery assembled by attaching lithium sheets on both sides of the Li6PS5Cl sulfide solid electrolyte in Comparative Example 2 was subjected to cycle testing using a BlueDian CT2001A battery testing system at a current density of 0.1 mA cm -2 , the lithium / / lithium symmetrical battery can be stably cycled for 1500 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 600 cycles, the capacity retention rate was 76.3%.

[0118] Comparative Example 3

[0119] The difference between Comparative Example 3 and Example 1 is that the preparation method of Comparative Example 3 is as follows: Li2S, GeS2, P2S5 and MgF2 (about 1 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is argon gas), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 10.01 GeP 1.99 Mg 0.01 S 11.98 F 0.02 Precursor powder;

[0120] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 10.01 GeP 1.99 Mg 0.01 S 11.98 F 0.02 Sulfide solid electrolyte.

[0121] Measure output 10.01 GeP 1.99 Mg 0.01 S 11.98 F 0.02 The ionic conductivity of the sulfide solid electrolyte at 25°C is 3.21 mS cm -1 , only Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is 51%. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.49 cm 3 g -1 , and its ionic conductivity retention rate is 11%.

[0122] Li in the above comparative example 3 10.01 GeP 1.99 Mg 0.01 S 11.98 F 0.02 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.1 mA cm -2 The lithium / lithium symmetric battery cycled stably for 500 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 cathode, and metallic lithium anode were assembled into an all-solid-state battery. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 3.0 to 4.2V. After 200 cycles, the capacity retention rate was 72.8%.

[0123] Comparative Example 4

[0124] The difference between Comparative Example 4 and Example 7 is that the preparation method of Comparative Example 4 is as follows: Li2S, P2S5, LiCl and MgF2 (about 1 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is vacuum or argon), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 6.03 P 0.99 Mg 0.01 S5Cl 0.98F 0.02 Precursor powder;

[0125] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 580°C under an inert atmosphere (argon) for 10 hours, and finally cooled to room temperature and ground to obtain Li 6.03 P 0.99 Mg 0.01 S5Cl 0.98 F 0.02 Sulfide solid electrolyte.

[0126] Measure output 6.03 P 0.99 Mg 0.01 S5Cl 0.98 F 0.02 The ionic conductivity of the sulfide solid electrolyte at 25°C is 1.82 mS cm -1 , which is only 56% of the ionic conductivity of Li6PS5Cl in Comparative Example 2. In addition, after exposure to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 1.12 cm 3 g -1 , and its ionic conductivity retention rate is 5%.

[0127] The Li in the above comparative example 4 6.03 P 0.99 Mg 0.01 S5Cl 0.98 F 0.02 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 , the lithium / / lithium symmetric battery can be stably cycled for 1800 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 500 cycles, the capacity retention rate was 58.8%.

[0128] Comparative Example 5

[0129] The difference between Comparative Example 5 and Example 4 is that the preparation method of Comparative Example 5 is as follows: Li2S, GeS2, P2S5 and SbF3 (about 2 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is vacuum), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li9.94 GeP 1.98 Sb 0.02 S 11.94 F 0.06 Precursor powder;

[0130] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.94 GeP 1.98 Sb 0.02 S 11.94 F 0.06 Sulfide solid electrolyte.

[0131] Measure output 9.94 GeP 1.98 Sb 0.02 S 11.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 4.55 mS cm -1 , only Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is 74%. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.48 cm 3 g -1 , and its ionic conductivity retention rate is 21%.

[0132] Li in the above comparative example 3 9.94 GeP 1.98 Sb 0.02 S 11.94 F 0.06 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 The lithium / lithium symmetric battery cycled stably for 600 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 cathode, and metallic lithium anode were assembled into an all-solid-state battery. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 3.0 to 4.2V. After 600 cycles, the capacity retention rate was 73.1%.

[0133] Comparative Example 6

[0134] The difference between Comparative Example 6 and Example 9 is that the preparation method of Comparative Example 6 is as follows: Li2S, P2S5, LiCl and SbF3 (about 2 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is argon gas), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 6.04 P 0.98 Sb 0.02 S5Cl 0.94 F 0.06 Precursor powder;

[0135] The precursor powder was calcined in a muffle furnace at a heating rate of 5°C / min to 580°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 6.04 P 0.98 Sb 0.02 S5Cl 0.94 F 0.06 Sulfide solid electrolyte.

[0136] Measure output 6.04 P 0.98 Sb 0.02 S5Cl 0.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 1.99 mS cm -1 , which is only 62% of the ionic conductivity of the Li6PS5Cl sulfide solid electrolyte in Comparative Example 2. In addition, after exposure to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 0.88 cm 3 g -1 , and its ion conductivity retention rate is 30%.

[0137] Li in the above comparative example 6 6.04 P 0.98 Sb 0.02 S5Cl 0.94 F 0.06 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 , the lithium / / lithium symmetrical battery can be stably cycled for 2000 hours at room temperature. 0.8 Co 0.1 Mn 0.1An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 800 cycles, the capacity retention rate was 72.2%.

[0138] Comparative Example 7

[0139] The difference between Comparative Example 7 and Example 4 is that the preparation method of Comparative Example 7 is as follows: Li2S, GeS2, P2S5 and ScF3 (about 2 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is vacuum or argon), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 9.98 GeP 1.98 Sc 0.02 S 11.94 F 0.06 Precursor powder;

[0140] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.98 GeP 1.98 Sc 0.02 S 11.94 F 0.06 Sulfide solid electrolyte.

[0141] Measure output 9.98 GeP 1.98 Sc 0.02 S 11.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 3.56 mS cm -1 , only Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is 58%. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.52 cm 3 g -1 , and its ionic conductivity retention rate is 18%.

[0142] Li in the above comparative example 7 9.98 GeP 1.98 Sc 0.02 S 11.94 F 0.06 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm-2 The lithium / lithium symmetric battery cycled stably for 500 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 cathode, and metallic lithium anode were assembled into an all-solid-state battery. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 3.0 to 4.2V. After 300 cycles, the capacity retention rate was 68.5%.

[0143] Comparative Example 8

[0144] The difference between Comparative Example 8 and Example 9 is that the preparation method of Comparative Example 8 is as follows: Li2S, P2S5, LiCl and ScF3 (about 2 mol%) are weighed according to the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is vacuum), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 6.04 P 0.98 Sc 0.02 S5Cl 0.94 F 0.06 Precursor powder;

[0145] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 580°C under an inert atmosphere (argon) for 10 hours, and finally cooled to room temperature and ground to obtain Li 6.04 P 0.98 Sc 0.02 S5Cl 0.94 F 0.06 Sulfide solid electrolyte.

[0146] Measure output 6.02 P 0.99 Sc 0.01 S5Cl 0.97 F 0.03 The ionic conductivity of the sulfide solid electrolyte at 25°C is 1.37 mS cm -1 , which is only 43% of the ionic conductivity of Li6PS5Cl in Comparative Example 2. In addition, after exposure to moist air at 25°C and 38% relative humidity for 10 minutes, the total amount of hydrogen sulfide released was 0.92 cm 3 g -1 , and its ionic conductivity retention rate is 8%.

[0147] Li in the above comparative example 8 6.04 P 0.98 Sc 0.02 S5Cl 0.94 F 0.06The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 , the lithium / / lithium symmetric battery can be stably cycled for 1700 hours at room temperature. 0.8 Co 0.1 Mn 0.1 An all-solid-state battery is assembled using an O2 positive electrode and a metallic lithium negative electrode. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 0.5C over a voltage range of 2.5 to 4.3V. After 700 cycles, the capacity retention rate was 68.7%.

[0148] Comparative Example 9

[0149] The difference between Comparative Example 9 and Example 4 is that the preparation method of Comparative Example 9 is as follows: Li2S, GeS2, P2S5 and BiF3 (about 2 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is vacuum), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 9.98 GeP 1.98 Bi 0.02 S 11.94 F 0.06 Precursor powder;

[0150] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.98 GeP 1.98 Bi 0.02 S 11.94 F 0.06 Sulfide solid electrolyte.

[0151] Measure output 9.98 GeP 1.98 Bi 0.02 S 11.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 4.62 mS cm -1 , only Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is 75%. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.48 cm 3 g -1 , and its ionic conductivity retention rate is 24%.

[0152] Li in the above comparative example 9 9.98 GeP 1.98 Bi 0.02 S 11.94 F 0.06 The lithium / lithium symmetrical battery, with lithium sheets attached to both sides of the sulfide solid electrolyte, was cycled using a BlueDian CT2001A battery test system at a current density of 0.1 mA cm -2 The lithium / lithium symmetric battery cycled stably for 650 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 cathode, and metallic lithium anode were assembled into an all-solid-state battery. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 3.0 to 4.2V. After 550 cycles, the capacity retention rate was 70.2%.

[0153] Comparative Example 10

[0154] The difference between Comparative Example 10 and Example 4 is that the preparation method of Comparative Example 10 is as follows: Li2S, GeS2, P2S5 and InF3 (about 2 mol%) are weighed in accordance with the stoichiometric ratio and placed in a ball mill for high-energy ball milling (the atmosphere in the ball mill is vacuum), with a ball-to-material ratio of 20:1 and a rotation speed of 600 rpm. After ball milling for 12 hours, Li 9.96 Ge 0.98 ln 0.02 P2S 11.94 F 0.06 Precursor powder;

[0155] The precursor powder was calcined in a muffle furnace at a heating rate of 4°C / min to 680°C under an inert atmosphere (argon) for 8 hours, and finally cooled to room temperature and ground to obtain Li 9.96 Ge 0.98 ln 0.02 P2S 11.94 F 0.06 Sulfide solid electrolyte.

[0156] Measure output 9.96 Ge 0.98 ln 0.02 P2S 11.94 F 0.06 The ionic conductivity of the sulfide solid electrolyte at 25°C is 5.21 mS·cm -1 , only Li in Comparative Example 1 10 GeP2S 12 The ionic conductivity of the sulfide solid electrolyte is 85%. In addition, after exposure to moist air at 25°C and 38% relative humidity for 120 minutes, the total amount of hydrogen sulfide released is 0.41 cm3 g -1 , and its ionic conductivity retention rate is 22%.

[0157] The Li in the above Comparative Example 10 was 9.99 Ge 0.99 ln 0.01 P2S 11.97 F 0.03 The lithium-ion battery was assembled with lithium sheets attached to both sides of the sulfide solid electrolyte. The cycle test was performed using a Blue Power CT2001A battery test system with a current density of 0.1 mA cm -2 The lithium / lithium symmetric battery cycled stably for 550 hours at room temperature. Furthermore, the sulfide solid electrolyte, LiCoO2 cathode, and metallic lithium anode were assembled into an all-solid-state battery. The battery's electrochemical performance was tested using a Blue Power CT2001A battery test system. The battery was charged and discharged at a constant rate of 1C over a voltage range of 3.0 to 4.2V. After 500 cycles, the capacity retention rate was 66.8%.

[0158] It can be seen from the above embodiments and comparative examples that when the fluorine source is SnF2, the prepared fluorine-doped sulfide solid electrolyte has excellent ionic conductivity, high stability when exposed to humid air, and can be used in batteries to effectively improve the battery cycle stability and rate performance.

[0159] The various aspects, embodiments, and features of the present invention should be considered in all respects as illustrative and not limiting, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0160] In the preparation method of the present invention, the order of the steps is not limited to the order listed. Persons skilled in the art will appreciate that variations in the order of the steps are within the scope of the present invention without inventive effort. Furthermore, two or more steps or actions may be performed simultaneously.

[0161] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit its implementation. Persons skilled in the art may make various modifications, additions, or substitute similar methods for the described specific embodiments. It is not necessary and impossible to provide comprehensive examples of all implementations here. However, obvious variations or modifications arising from the essential spirit of the present invention remain within the scope of protection of the present invention, and interpreting them as any additional limitations would be contrary to the spirit of the present invention.

Claims

1. A fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability, characterized in that: It has the chemical formula shown in Formula I or Formula II: Li 10-2x Ge 1-x Sn x P2S 12-2x F 2x Formula I Among them, 0<x<1; Li 6±3y P 1-y Sn y S5Cl 1-2y F 2y type II Among them, 0<y<1.

2. The fluorine-doped sulfide solid electrolyte according to claim 1, characterized in that In formula I, 0<x≤0.1; in formula II, 0<y≤0.

1.

3. The fluorine-doped sulfide solid electrolyte according to claim 1, characterized in that The raw materials for preparing the fluorine-doped sulfide solid electrolyte of the chemical formula shown in Formula I include: a lithium source, a germanium source, a phosphorus source and a fluorine source; the raw materials for preparing the fluorine-doped sulfide solid electrolyte of the chemical formula shown in Formula II include: a lithium source, a phosphorus source, a chlorine source and a fluorine source; the fluorine source is SnF2.

4. The fluorine-doped sulfide solid electrolyte according to claim 3, characterized in that The lithium source is lithium sulfide; the germanium source is germanium sulfide; the phosphorus source is phosphorus sulfide; and the chlorine source is lithium chloride.

5. The fluorine-doped sulfide solid electrolyte according to claim 1, characterized in that The fluorine-doped sulfide solid electrolyte of the chemical formula represented by Formula I has an ionic conductivity of ≥4.0 mS / cm at 25° C., and the fluorine-doped sulfide solid electrolyte of the chemical formula represented by Formula II has an ionic conductivity of ≥2.0 mS / cm at 25° C.; And / or, the fluorine-doped sulfide solid electrolyte of the chemical formula I is exposed to air at 35-40% relative humidity at 25°C for 120 minutes, and the total amount of hydrogen sulfide released is ≤1.0 cm 3 / g, ionic conductivity retention rate ≥15%; the fluorine-doped sulfide solid electrolyte of the chemical formula shown in Formula II is exposed to air at 35-40% relative humidity at 25°C for 10 minutes, and the total amount of hydrogen sulfide released is ≤1.5cm 3 / g, ion conductivity retention rate ≥10%.

6. A method for preparing a fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability, characterized in that: The following steps are involved: Weighing a lithium source, a germanium source, a phosphorus source, and a fluorine source in a stoichiometric ratio according to Formula I, or weighing a lithium source, a phosphorus source, a chlorine source, and a fluorine source in a stoichiometric ratio according to Formula II, and mechanically mixing them to obtain a precursor powder; The precursor powder is subjected to high-temperature calcination treatment and then cooled to room temperature to obtain the fluorine-doped sulfide solid electrolyte with high ionic conductivity and stability.

7. The preparation method according to claim 6, characterized in that The lithium source is lithium sulfide; the germanium source is germanium sulfide; the phosphorus source is phosphorus sulfide; the chlorine source is lithium chloride; and the fluorine source is SnF2.

8. The preparation method according to claim 6, characterized in that The mechanical mixing includes one or more of high-energy ball milling, mechanical stirring, mechanical shaking, and roller milling, and the mixing time is 0.1 to 48 hours.

9. The preparation method according to claim 6, characterized in that The conditions for the high-temperature calcination treatment include: a calcination temperature of 500 to 700° C. and a calcination time of 0.1 to 24 hours under an inert atmosphere.

10. An all-solid-state lithium secondary battery, characterized in that: The invention comprises a positive electrode, a negative electrode and a fluorine-doped sulfide solid electrolyte prepared by the preparation method according to claim 1 or claim 6.

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