CN106684460A - Lithium sulfide solid electrolyte material with addition of lithium-tin alloy and silver halogen compound and preparation method thereof - Google Patents

Abstract

The invention discloses a lithium sulfide solid electrolyte material with the addition of lithium-tin alloy and a silver halogen compound and a preparation method thereof. The preparation method comprises the following steps: (1) weighing lithium sulfide, phosphorus sulfide, lithium-tin alloy powder and sulfur according to the molar ratio of (2.5 to 4.0) to (0.5 to 1.0) to (0.02 to 0. 1) to (0.01 to 0.05) under an atmosphere protection condition, and uniformly mixing, thus obtaining a lithium-sulfur-phosphorus-tin mixture; (2) taking and putting the lithium-sulfur-phosphorus-tin mixture, silver iodide, silver bromide and silver chloride in a ball-milling tank under atmosphere protection and safe red light conditions, and carrying out ball milling, thus obtaining an amorphous lithium-sulfur-phosphorus-tin mixture containing the silver iodide, the silver bromide and the silver chloride; (3) sealing the amorphous lithium-sulfur-phosphorus-tin mixture obtained in the step (2) under the atmosphere protection condition, and heating to 60 to 180 DEG C under a vacuum condition for carrying out thermal treatment, thus obtaining the lithium sulfide solid electrolyte material. According to the preparation method disclosed by the invention, the lithium ionic conductivity of the obtained lithium sulfide solid electrolyte material is increased by simultaneously adding the lithium-tin alloy and the silver halogen compound.

Description

A lithium sulfide solid electrolyte material added with lithium tin alloy and silver halide compound Materials and their preparation methods

technical field

The invention relates to a lithium sulfide solid electrolyte material, in particular to a lithium sulfide solid electrolyte material added with a lithium tin alloy and a silver halide compound and a preparation method thereof.

Background technique

Lithium-ion batteries with high energy density have shown more and more important market prospects as power batteries for electric vehicles and have been widely valued. A general lithium-ion battery is composed of a positive electrode, a negative electrode, a diaphragm, an organic electrolyte, and a sealed casing. Major safety accidents such as fires caused by flammable organic electrolytes occur from time to time. Although many studies have greatly improved the performance of lithium-ion batteries in terms of material modification and battery structure, the safety problems of lithium-ion batteries containing organic electrolytes in use have not been fundamentally resolved.

The use of solid lithium-ion electrolyte materials to replace flammable organic electrolyte solutions is the best way to solve the safety problems of lithium-ion batteries in use. An all-solid lithium-ion battery is usually composed of a positive electrode film, a negative electrode film, and an all-solid lithium-ion electrolyte membrane between the positive and negative electrode layers. This simple layered all-solid-state Li-ion battery has received increasing attention in recent years due to its high safety due to the absence of flammable organic electrolyte solutions. The all-solid lithium-ion battery is a series laminated structure of powder films, so it can further reduce manufacturing costs, improve production efficiency, and can also achieve high voltage, which greatly improves the energy density of the battery.

The key material of an all-solid lithium-ion battery is an all-solid electrolyte material suitable for lithium-ion conduction and having high lithium-ion conductivity. In November 2000, in the abstract of the 26th Symposium on Solid State Ionics in Japan (p174), it was reported that a mixture of lithium sulfide (Li ₂ S) and phosphorus sulfide P ₂ S ₅ could form a lithium ion conductor after heat treatment at 200 degrees. As a result, amorphous lithium sulfide-based solid electrolytes have gradually become a hot material in the research and development of all-solid lithium batteries.

The lithium ion solid electrolyte should have the following characteristics: ① the lithium ion in the lithium ion carrier compound should be easily polarized, that is, the binding force is relatively small and easy to migrate; ② the lithium ion density of the lithium ion solid electrolyte should be as high as possible, that is, Lithium ions that contribute to lithium ion conduction must exist in large quantities; ③The diffusion of lithium ions in solid electrolytes is through the rapid diffusion of atomic vacancies, structural relaxation and structural defects in the matrix in amorphous or quasi-crystalline solid electrolytes and other The large number of atomic vacancies introduced by the method will promote the rapid diffusion of lithium ions through the atomic vacancies and show high lithium ion conductivity. Lithium sulfide-based materials with high lithium-ion conductivity are suitable for use as solid electrolytes for all-solid-state lithium-ion batteries.

Existing studies have shown that adding other components to lithium sulfide-based solid electrolyte materials can improve ion conductivity. For example, the invention patent with the publication number CN101013761A discloses three types of solid electrolyte material systems for all-solid-state lithium-ion batteries, which are respectively : (A) Li ₂ S+A/I, where A/I is AlI ₃ , ZnI ₂ , ZrI ₄ or LaI ₃ , 0.5≤x≤1.5; (B)yLi ₂ S-mA/I-zB/S , where y+z=9, y from 5.0 to 7.0, m from 0.5 to 3, B/S is SiS ₂ , 0.5P ₂ S ₅ , CeS ₂ or 0.5B ₂ S ₃ ; A/I is AlI ₃ , ZnI ₂ , ZrI ₄ or LaI ₃ ; (C)yLi ₂ S-mA/I-zB/S-nLiI, where y+z=9, y from 5.0 to 7.0, m from 0.5 to 3.0, n from 0.5 to 3.0, A/I is AlI ₃ , ZnI ₂ , ZrI ₄ or LaI ₃ ; B/S is SiS ₂ , 0.5P ₂ S ₅ , CeS ₂ or 0.5B ₂ S ₃ . The preparation method of these three types of solid electrolyte materials is as follows: After the batching is completed, they are placed in a quartz glass tube for vacuum packaging, and then reacted at a high temperature of 500-750° C. for 10-14 hours, then quenched to room temperature, and ground into powder. The structure of the solid electrolyte prepared according to the technical scheme of the invention is amorphous. Although the invention can improve the ion migration ability, the improvement of the ion conductivity of the obtained material is not ideal. 6Li ₂ S-0.5AlI ₃ - Take the 3SiS ₂ -LiI system as an example (y=6, m=0.5, z=3, n=1), this system is mainly a lithium ion conductor at room temperature and higher temperature (≤200°C), and its total conductance at room temperature The highest rate is only 3.80×10 ^-6 S/cm. As another example, CN101013753A also discloses a sulfide-based solid electrolyte material for all-solid-state lithium batteries, which is compounded according to the molar ratio of Li ₂ S:A/S:P ₂ S ₅ =6:0.1-4.0:1.5 In the formula, A is Ag, Zn, Al or Zr; its preparation process is to mix the ingredients and place them in a quartz glass tube for vacuum packaging, slowly raise the temperature to 450°C and keep it for 24 hours, then raise the temperature to 500-750°C for 10 -After 14 hours, it was cooled to room temperature and ground into powder. The improvement of the ionic conductivity of the solid electrolyte obtained by the invention is also not satisfactory, and the total conductivity at room temperature is also 10 ^-6 S/cm. The applicant believes that in the above invention patents (1) the additives (such as iodide or sulfide, etc.) are stable hexagonal or orthorhombic crystals, and no more atomic vacancies are introduced into the system, which cannot be lithium ions. Diffusion provides more diffusion channels; (2) The content of additives is too high, which reduces the proportion of lithium sulfide as a lithium ion carrier in the solid electrolyte ingredients, directly reducing the density of migratable lithium ions that contribute to lithium ion conduction ; (3) The high content of additives not only did not increase the diffusion channels of lithium ions in the solid electrolyte, but hindered the diffusion of lithium ions. Therefore, the ingredients added in the above invention patents did not significantly improve the ion conductivity of the sulfide-based solid electrolyte.

The invention patent with the publication number CN104752756A discloses a preparation method of a solid electrolyte material with high ion conductivity. The material is mainly composed of silver iodide, and the molar ratio is Ag ₂ S:P ₂ S ₅ :AgI=3:1: 14 Ag ⁺ ion-conducting solid electrolyte prepared by high-energy ball milling reaction after mixing ingredients. Although the solid electrolyte prepared by the method described in this invention has higher room temperature ionic conductivity (up to 10 ^-3 S/cm), what this invention utilizes is the ionic conductivity characteristic of silver iodide, through a small amount of phosphorus sulfide Combined with silver iodide for amorphization to form a fast channel for Ag ⁺ conduction, which facilitates the migration of Ag ⁺ , thereby improving the ionic conductivity of the material. It can be seen that this invention does not increase the diffusion channel of lithium ions by generating atomic vacancies that can be used for lithium ion diffusion, thereby achieving the effect of improving the lithium ion conductivity of sulfide-based solid electrolytes; the applicant believes that this invention is a A solid electrolyte that does not contain lithium ions but relies on Ag ⁺ to conduct electricity is not suitable for use as a solid electrolyte between the positive and negative electrodes of an all-solid lithium battery ^. When charging and discharging, Ag ⁺ migrates to the interface with low potential to form a barrier that hinders the passage of lithium ions, which will lead to the consumption of a large amount of lithium ions, and the cycle characteristics of the battery will be difficult to maintain.

On the other hand, the research on tin-based materials first originated from Japan's Seiko Electronics Industry Company, and then Sanyo Electric, Matsushita Electric, Fuji Film and other companies successively carried out research (such as the invention patents of CN1930726A and CN101887965A), but these studies only use lithium Tin alloy powder, as a battery anode material suitable for lithium ion intercalation, is used as an anode material for thermal batteries, lithium ion batteries, lithium ion capacitors, lithium sulfur batteries, and lithium air batteries to accept the insertion of lithium ions during charging. Related studies involving the simultaneous addition of lithium-tin alloys, silver iodide, silver bromide, and silver chloride to increase the density of mobile lithium ions in solid electrolytes.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method that, on the one hand, can form a large number of atomic vacancies that can be used for lithium ion diffusion, and on the other hand, can increase the concentration of lithium ions that can migrate in lithium sulfide-based solid electrolytes, thereby effectively increasing the concentration of sulfide-based solid electrolytes. Lithium sulfide solid electrolyte material with added lithium tin alloy and silver halide compound and its preparation method.

The preparation method of the lithium sulfide series solid electrolyte material adding lithium tin alloy and silver halide compound according to the present invention comprises the following steps:

1) Under atmosphere protection conditions, weigh lithium sulfide, phosphorus sulfide, lithium tin alloy powder and sulfur at a molar ratio of 2.5-4.0:0.5-1.0:0.02-0.1:0.01-0.05, and mix them uniformly to obtain lithium sulfur phosphorus tin mixture;

2) Under the conditions of atmosphere protection and safe red light, take lithium sulfur phosphorus tin mixture, silver iodide equivalent to 1-3% of its mass, silver bromide equivalent to 1-3% of its mass, and 1-3% of its mass % of silver chloride, placed in a ball mill jar for ball milling, to obtain an amorphous lithium sulfophosphorus tin mixture containing silver iodide, silver bromide and silver chloride; wherein, the total addition of silver iodide, silver bromide and silver chloride is less than Or equal to 5% of the mass of lithium sulfur phosphorus tin mixture;

3) The resulting amorphous lithium-thion-phosphorus-tin mixture containing silver iodide, silver bromide and silver chloride is sealed under atmosphere protection conditions, and then heated to 60-180°C under vacuum conditions for heat treatment to obtain lithium-tin alloy and Lithium sulfide solid electrolyte material of silver halide compound.

In step 1) of the above method, the molar ratio of lithium sulfide, phosphorus sulfide, lithium-tin alloy powder and sulfur is preferably 2.5-3.0:0.5-0.75:0.05-0.10:0.01-0.05. The lithium-tin alloy powder (Li ₂₂ Sn ₅ ) is preferably -300 mesh powder, and the sulfur is preferably -200 mesh elemental sulfur powder.

In step 1) of the above method, the atmosphere protection is usually under the protection of an inert gas, such as conventionally used inert gases such as argon and nitrogen. The specific operation is usually carried out in a glove box with argon protection.

In the step 1) of the above method, the existing conventional ball milling method can be used to mix the components evenly. During the ball milling, dry ball milling or medium ball milling can be used. During the ball milling, zirconia grinding balls are used. The mass ratio of the ball to material is preferably 2: 0.5-1 (mass ratio). When using a conventional rolling ball mill, it usually takes 6-10 hours to mix lithium sulfide and phosphorus sulfide uniformly, and when using a planetary high-energy ball mill, it usually takes 2-5 hours to mix lithium-tin alloy, sulfur, lithium sulfide and phosphorus sulfide uniformly.

In step 2) of the above method, the atmosphere protection is usually under the protection of an inert gas, such as conventionally used inert gases such as argon and nitrogen. The specific operation is usually carried out in a glove box with argon protection.

In step 2) of the above method, the silver iodide is preferably -200 mesh silver iodide powder, the silver bromide is preferably -200 mesh silver bromide powder, and the silver chloride is preferably -200 mesh silver bromide powder. For ball milling, zirconia grinding balls are used, and the ball-to-material ratio is preferably 2:0.5-1 (mass ratio), more preferably 2:0.7 (mass ratio). In this step, the ball milling time to obtain the amorphous lithium phosphotin mixture containing silver iodide, silver bromide and silver chloride is usually 30-48h. Crystalline lithium sulfur phosphorus tin mixture, it is preferable to stir the mixture of silver iodide, silver bromide and silver chloride and lithium sulfur phosphorus tin evenly and then put it into a ball mill jar for ball milling. At this time, the ball milling time can be controlled at 30-40h. Complete amorphization of the lithium phosphostin mixture and thorough mixing of silver iodide, silver bromide and silver chloride with the lithium phosphostin mixture.

In step 3) of the above method, the atmosphere protection is usually under the protection of an inert gas, such as conventionally used inert gases such as argon and nitrogen. The specific sealing operation is usually carried out in a glove box with argon protection.

In the step 3) of above-mentioned method, heat treatment operation is carried out to promote the part silver ion in silver iodide, silver bromide and silver chloride to combine with surrounding sulfur to form nanoscale silver sulfide (precipitation in situ), impel the formation of silver sulfide with iodine, bromine or chlorine A large number of atomic vacancies that can be used as diffusion channels for lithium ions are formed in the main cubic structure, and part of lithium iodide, lithium bromide and lithium chloride (in-situ precipitation) are formed at the same time; at the same time, amorphous lithium Part of the lithium of tin reacts with the surrounding sulfur to form lithium sulfide and lithium-containing tin-based nanocrystals or nanoclusters. The newly formed lithium sulfide increases the concentration of mobile lithium ions in the solid electrolyte system, and the newly formed tin-based Nanocrystals or nanoclusters are incomplete crystals, and their structure also has a large number of atomic vacancies. When lithium ions in the solid electrolyte system migrate to the positions of lithium-containing tin-based nanocrystals or nanoclusters and amorphous lithium tin, It will have the advantages of vacancy diffusion and lithium ion exchange diffusion at the same time, thereby preparing a multi-component mixture solid electrolyte powder with high lithium ion concentration and high atomic vacancies. In this step, the heat treatment time is generally greater than or equal to 1 h, preferably 1-5 h; the heat treatment temperature is more preferably 80-160° C., and under this temperature condition, the heat treatment time is preferably 1-3 h.

The present invention also includes the lithium sulfide-based solid electrolyte material prepared by the above method with addition of lithium tin alloy and silver halide compound.

Compared with prior art, the present invention is characterized in that:

1. In the present invention, lithium sulfide and phosphorus sulfide are used as substrates, and lithium-tin alloys, sulfur, silver iodide, silver bromide and silver chloride are added in specific proportions after high-energy ball milling to form an amorphous sulfide mixture. The effect of adding ingredients lithium tin alloy, sulfur, silver iodide, silver bromide and silver chloride evenly distributed in the matrix; silver iodide transforms into a stable body-centered cubic crystal with a "rigid skeleton" composed of iodide ions at a higher temperature, Silver ions exist in body-centered cubic crystals made of iodide ions, while silver bromide and silver chloride are cubic crystals of sodium chloride structure, and silver ions exist in octahedral gaps made of chloride ions; further In the heat treatment process, part of the silver ions are separated from the cubic structure of silver iodide, silver bromide and silver chloride, and react with the surrounding sulfur to form nano-scale silver sulfide. The formed nano-scale silver sulfide can stabilize the solid electrolyte matrix. ; At the same time, a large number of interstitial vacancies suitable for the diffusion of lithium ions are formed in the cubic structure dominated by iodine, bromine and chloride ions, thereby effectively improving the ion conductivity of the sulfide-based solid electrolyte. / bromide / lithium chloride. At the same time, part of the lithium in the amorphous LiSn reacts with the surrounding sulfur during heat treatment to transform into lithium sulfide and tin-based nanocrystals or nanoclusters containing lithium, and the newly formed lithium sulfide improves the mobility in the solid electrolyte system. concentration of lithium ions, and the newly formed tin-based nanocrystals or nanoclusters are incomplete crystals, and their structure also has a large number of atomic vacancies. Lithium ions in the solid electrolyte system are migrating to tin-based nanocrystals or nanoclusters containing lithium When the position of clusters and amorphous lithium tin, it will have the advantages of vacancy diffusion and lithium ion exchange diffusion at the same time, so as to prepare a multi-component mixture solid electrolyte powder with high lithium ion concentration and high atomic vacancies.

2. The product nano-silver sulfide and iodine/bromine/lithium chloride of the in-situ precipitation reaction during heat treatment in the method of the present invention all have ion conductivity, which can further improve the lithium ion conductivity of lithium sulfide-based solid electrolytes. The formed nano-silver sulfide particles can obtain a dispersion strengthening effect, and the nano-silver sulfide particles dispersed in the mixture can stabilize the microstructure of the lithium sulfide-based solid electrolyte and inhibit the multi-component mixture solid electrolyte powder in the process of charging and discharging. organizational changes.

detailed description

The present invention will be described in further detail below in conjunction with specific examples to better understand the content of the present invention, but the present invention is not limited to the following examples.

The reagents used in the following examples, such as lithium sulfide (Li ₂ S), phosphorus sulfide (P ₂ S ₅ ) and sulfur, are all chemically pure reagents with a purity of 99.9%.

Example 1

1) Mixed high energy ball milling process:

In a glove box protected by an argon atmosphere with low moisture (≤1ppm) and low oxygen content (≤1ppm), the molar ratio of lithium sulfide, phosphorus sulfide, lithium-tin alloy powder and sulfur powder is 4:1:0.1: The ratio of 0.05 is mixed, mixed with zirconia balls with a diameter of 3-10mm, and then sealed into a ball mill tank. The mass ratio of the zirconia balls in the tank to the mixture is 2:0.7; the sealed ball mill cans In the planetary high-energy ball mill, dry mixing ball milling is adopted, and the ball milling time is 5 hours to obtain the lithium sulfur phosphorus tin mixture;

2) Second high energy ball milling process:

In a glove box protected by an argon atmosphere with low moisture (≤1ppm) and low oxygen content (≤1ppm) with safe lights (such as red light), put silver iodide powder equivalent to 1% of the mass of the above lithium sulfur phosphorus tin mixture (particle size is 300 mesh), silver bromide powder (particle size is 300 mesh) corresponding to 1% of the above-mentioned lithium sulfur phosphorus tin mixture mass and silver chloride powder (particle size is 300 mesh) equivalent to 1% of the above lithium sulfur phosphorus tin mixture mass mesh) and the mixture of lithium sulfur, phosphorus and tin are manually stirred and mixed, and the obtained mixed material is mixed with zirconia balls with a diameter of 3-10mm according to the mass ratio of balls and materials of 2:0.7, and then sealed into a ball mill jar, sealed, and the sealed ball mill jar Loading into a planetary high-energy ball mill and carrying out high-energy dry ball milling, the ball milling time is 36 hours, to obtain an amorphous lithium sulfur phosphorus tin mixture containing silver iodide, silver bromide and silver chloride;

3) Heat treatment process:

The resulting amorphous lithium phosphotin mixture containing silver iodide, silver bromide and silver chloride is sealed in a glove box with argon atmosphere protection of low moisture (≤1ppm), low oxygen content (≤1ppm), and then Heating to 150° C. for 2 hours under vacuum conditions to obtain the lithium sulfide-based solid electrolyte material added with lithium-tin alloy and silver halide compound of the present invention.

After the solid electrolyte powder prepared in this example was pressed into a standard sample, the ion conductivity of the sample in this example was measured to be 2.9×10 ^-4 at a room temperature of 25°C by using a CHI660 electrochemical workstation and using an AC impedance method. S/cm.

comparative example

In a glove box with low moisture (≤1ppm) and low oxygen content (≤1ppm) protected by an argon atmosphere, lithium sulfide and phosphorus sulfide are dosed and mixed in a molar ratio of 4:1, mixed with zirconia balls After matching, it is sealed into a ball milling tank. The mass ratio of the zirconia balls in the tank to the mixture is 2:0.7; the sealed ball milling tank is packed in a planetary high-energy ball mill and pre-mixed with a dry ball mill. The milling time is 36 hours, the lithium sulfur phosphorus ternary mixture solid electrolyte powder was obtained.

After the solid electrolyte powder prepared in this comparative example was pressed into a standard sample, the ion conductivity of the sample of this comparative example was measured to be 8.9×10 ^-6 at a room temperature of 25°C by using an electrochemical workstation CHI660 by AC impedance method S/cm.

Example 2

Repeat Example 1, the difference is:

In step 1), lithium sulfide, phosphorus sulfide, lithium-tin alloy powder and sulfur powder are mixed in a molar ratio of 2.5:0.5:0.02:0.01, and the ball milling time is 3 hours;

In step 2), the particle size of silver iodide powder, silver bromide powder and silver chloride powder is 250-300 mesh;

In step 3), the heat treatment is carried out at 120° C., and the heat treatment time is 5 hours.

After the solid electrolyte powder prepared in this example was pressed into a standard sample, the ion conductivity of the sample in this example was measured to be 5.1×10 ^-4 at a room temperature of 25°C by using a CHI660 electrochemical workstation by AC impedance method S/cm.

Example 3

Repeat Example 1, the difference is:

In step 1), lithium sulfide, phosphorus sulfide, lithium-tin alloy powder and sulfur powder are mixed in a molar ratio of 3.2:0.5:0.08:0.02, and the mass ratio of zirconia balls to the mixture is 2:0.5 , the ball milling time is 4 hours;

In step 2), the particle size of silver iodide powder, silver bromide powder and silver chloride powder is 200 orders, and the addition of silver iodide powder is equivalent to 2% of lithium sulfur phosphorous tin mixture quality, and the addition of silver bromide powder is equivalent to 1.5% of the mass of the lithium sulfur phosphorous tin mixture, the addition of silver chloride powder is equivalent to 1.5% of the mass of the lithium sulfur phosphorous tin mixture;

In step 3), the heat treatment is carried out at 180° C., and the heat treatment time is 1 hour.

After the solid electrolyte powder prepared in this example was pressed into a standard sample, the ion conductivity of the sample in this example was measured to be 5.7×10 ^-4 at a room temperature of 25°C by using a CHI660 electrochemical workstation by AC impedance method. S/cm.

Example 4

Repeat Example 1, the difference is:

In step 1), lithium sulfide, phosphorus sulfide, lithium-tin alloy powder and sulfur powder are mixed in a molar ratio of 2.8:0.6:0.03:0.02;

In step 2), the particle size of the silver iodide powder, the silver bromide powder and the silver chloride powder is 200-260 mesh, and the addition of the silver iodide powder is equivalent to 2% of the quality of the lithium sulfur phosphorus tin mixture, and the addition of the silver bromide powder is equivalent to Based on 1% of the mass of the lithium sulfur phosphorus tin mixture, the addition of silver chloride powder is equivalent to 2% of the mass of the lithium sulfur phosphorus tin mixture; the ball milling time is 40 hours;

In step 3), the heat treatment is carried out at 120° C., and the heat treatment time is 1 hour.

After the solid electrolyte powder prepared in this example was pressed into a standard sample, the ionic conductivity of the sample in this example was measured to be 4.5×10 ^-4 S by using the CHI660 electrochemical workstation and using the AC impedance method at a room temperature of 25°C. /cm.

Claims (7)

1. the preparation method of the lithium sulfide system solid electrolyte material of a kind of addition lithium-tin alloy and silver-colored halogen compound, including with Lower step：

1) under the conditions of atmosphere protection, by 2.5-4.0：0.5-1.0：0.02-0.1：The mol ratio of 0.01-0.05 weighs sulfuration Lithium, phosphoric sulfide, lithium-tin alloy powder and sulfur, mix homogeneously, obtain lithium sulfur phosphor tin mixture；

2) under the conditions of atmosphere protection and safe HONGGUANG, take lithium sulfur phosphor tin mixture, the silver iodide equivalent to its quality 1-3%, Silver monobromide equivalent to its quality 1-3% and the silver chloride equivalent to its quality 1-3%, are placed in ball milling in ball grinder, obtain Amorphous li sulfur phosphor tin mixture containing silver iodide, Silver monobromide and silver chloride；Wherein, silver iodide, Silver monobromide and silver chloride is total Addition is less than or equal to the 5% of lithium sulfur phosphor tin mixture quality；

3) amorphous li sulfur phosphor tin mixture of the gained containing silver iodide, Silver monobromide and silver chloride is sealed under the conditions of atmosphere protection, 60-180 DEG C be warming up under vacuum condition carry out heat treatment, that is, obtain adding the sulfur of lithium-tin alloy and silver-colored halogen compound Change lithium system solid electrolyte material.

2. preparation method according to claim 1, it is characterised in that：Step 3) in, time of heat treatment be more than or wait In 1h.

3. preparation method according to claim 1, it is characterised in that：Step 3) in, the time of heat treatment is 1-5h.

4. preparation method according to claim 1, it is characterised in that：Step 3) in, the temperature of heat treatment is 80-160 DEG C.

5. the preparation method according to any one of claim 1-4, it is characterised in that：Step 2) in, the time of ball milling is 30-48h。

6. preparation method according to claim 5, it is characterised in that：Step 2) in, ratio of grinding media to material during ball milling is 2：0.5- 1。

7. the addition lithium-tin alloy and the lithium sulfide system of silver-colored halogen compound that any one of claim 1-6 method is prepared is consolidated Body electrolyte.