Sulfide solid electrolyte and preparation method and application thereof

Abstract

The invention relates to the field of all-solid-state batteries, and particularly discloses a sulfide solid electrolyte as well as a preparation method and application thereof. The preparation raw materials, the auxiliary agent and the solvent are mixed to prepare the mixed slurry, so that the raw materials, the auxiliary agent and other components can be fully mixed, the materials can fully react in the subsequent reaction, then the solvent is evaporated at a high temperature, the solid solute is left, and the solid solute is treated by using a high-energy ball mill. The preparation raw materials and the auxiliary agent are mixed and react to generate a powder mixture, finally, the powder mixture is subjected to high-temperature and high-pressure treatment, and the sulfide solid electrolyte is obtained after cooling, so that the preparation amount of the sulfide solid electrolyte is effectively improved by integrating liquid and solid treatment methods, and the ionic conductivity of the sulfide solid electrolyte is also effectively improved; the performance of a battery prepared by using the sulfide solid electrolyte is improved, and the auxiliary agent can inhibit the growth of lithium dendrites, so that the chemical stability and environmental stability of the sulfide solid electrolyte are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of all-solid-state batteries, and particularly relates to a sulfide solid-state electrolyte and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of electric vehicles and renewable energy, the safety, energy density and cycle life of lithium ion batteries have become the focus of research. Although liquid electrolytes are widely used in traditional lithium ion batteries, they have high flammability and are not environmentally friendly. Especially under extreme conditions such as high temperature and high pressure, they are prone to leakage and combustion, which poses a safety hazard. In order to improve the safety and performance of the battery, the research on solid-state electrolytes has gradually become the development direction of the new generation of lithium battery technology.

[0003] Solid-state batteries have obvious advantages in safety and energy density compared with liquid batteries. Solid-state electrolytes have higher thermal stability and higher safety than liquid electrolytes. However, there are still some limitations in solid-state batteries. The current solid-state electrolyte is mainly sulfide solid-state electrolyte. This electrolyte has high sensitivity to moisture in the air. Trace amounts of moisture in the environment will cause hydrolysis reaction of the sulfide solid-state electrolyte, damage its structure, and reduce its ionic conductivity. Therefore, it is necessary to change the existing sulfide solid-state electrolyte and its preparation process to enhance its environmental stability. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a sulfide solid-state electrolyte and a preparation method and application thereof, so as to solve the problem of poor environmental stability of the sulfide solid-state electrolyte prepared by the traditional preparation method.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] A preparation method of a sulfide solid-state electrolyte comprises:

[0007] Mixing Li2S, P2S5, an auxiliary agent and a solvent uniformly to prepare a mixed slurry;

[0008] After the mixed slurry is uniformly stirred, the solvent is evaporated at high temperature to obtain a solid solute;

[0009] The solid solute is placed in a high-energy ball mill for treatment to obtain a powder mixture;

[0010] The powder mixture is treated at high temperature and constant temperature, and the sulfide solid-state electrolyte is obtained after cooling;

[0011] The foregoing steps are all carried out in a sealed inert gas atmosphere.

[0012] Preferably, the auxiliary agent comprises LiCl and Sc2O3, and the mixing ratio of the Li2S, P2S5, LiCl and Sc2O3 is 2.54:0.48:1:0.02.

[0013] Preferably, the solvent comprises tetrahydrofuran, DME, ACN, ethyl acetate and ethanol.

[0014] Preferably, the solvent evaporation condition comprises:

[0015] 150-200℃ flowing hot gas flow, the flow rate of the hot gas flow is 250L / h, the pressure of the hot gas flow is 10-20bar, the hot gas flow is inert gas or carbon dioxide;

[0016] The mixed slurry is stirred while evaporating until the solid solute is obtained.

[0017] Preferably, the working condition of the high-energy ball mill comprises a rotating speed of 60-300rpm, a ball milling time of 60-120h and a ball-to-material ratio of 5-30:1.

[0018] Preferably, the high-temperature constant temperature treatment temperature is 550℃, the constant temperature treatment time is 7-10h, and the heating and cooling rate is 0.5℃ / min.

[0019] A sulfide solid electrolyte prepared by a preparation method of a sulfide solid electrolyte.

[0020] Preferably, the D50 of the sulfide solid electrolyte is 0.01-5μm.

[0021] The sulfide solid electrolyte prepared by the preparation method of a sulfide solid electrolyte is applied in liquid lithium ion batteries and solid-state lithium ion batteries.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The present application first mixes the preparation raw material, auxiliary agent and solvent to prepare a mixed slurry, so that the components such as the raw material and the auxiliary agent can be fully mixed, and the materials can be fully reacted in the subsequent reaction, then the solvent is evaporated at high temperature to leave a solid solute, and the solid solute is treated by a high-energy ball mill, so that the preparation raw material and the auxiliary agent are mixed and reacted to generate a powder mixture, finally the powder mixture is treated at high temperature and high pressure, and the sulfide solid electrolyte is obtained after cooling, the liquid and solid treatment methods are combined, not only the preparation amount of the sulfide solid electrolyte can be effectively improved, but also the ionic conductivity of the sulfide solid electrolyte can be effectively improved, the performance of the battery prepared by using the sulfide solid electrolyte is improved, and the addition of the auxiliary agent can inhibit the growth of lithium dendrites and improve the chemical stability and environmental stability of the sulfide solid electrolyte. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The preparation method of the present application is schematically shown. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] Embodiment one:

[0027] Please refer to Figure 1 The preparation method of a sulfide solid electrolyte comprises:

[0028] Mixing Li2S, P2S5, an auxiliary agent and a solvent uniformly to prepare a mixed slurry;

[0029] After the mixed slurry is stirred uniformly, the solvent is evaporated at high temperature to obtain a solid solute;

[0030] The solid solute is placed in a high-energy ball mill for processing to obtain a powder mixture;

[0031] The powder mixture is treated at high temperature and constant temperature, and the sulfide solid electrolyte is obtained after cooling;

[0032] The foregoing steps are all carried out in a sealed inert gas atmosphere.

[0033] As can be seen from the above, the raw materials, the auxiliary agent and the solvent are first mixed to prepare a mixed slurry, so that the raw materials and the auxiliary agent and other components can be mixed sufficiently, facilitating the full reaction between the materials in the subsequent reaction. Then the solvent is evaporated at high temperature to leave a solid solute, and the solid solute is processed using a high-energy ball mill, so that the raw materials and the auxiliary agent are mixed and react to generate a powder mixture. Finally, the powder mixture is treated at high temperature and high pressure, and the sulfide solid electrolyte is obtained after cooling. The comprehensive liquid and solid treatment methods not only effectively improve the preparation amount of the sulfide solid electrolyte, but also effectively improve the ionic conductivity of the sulfide solid electrolyte, improve the performance of the battery prepared using the sulfide solid electrolyte, and the addition of the auxiliary agent can inhibit the growth of lithium dendrites and improve the chemical stability and environmental stability of the sulfide solid electrolyte.

[0034] The auxiliary agent comprises LiCl and Sc2O3, and the mixing ratio of the Li2S, P2S5, LiCl and Sc2O3 is 2.54:0.48:1:0.02, and the product generated by the reaction is a series of Li 6+2x P1-x Sc x S 5-1.5x O 1.5x Cl sulfide solid electrolyte improves the ionic conductivity and air stability of sulfide electrolyte by introducing different elements. In addition, other rare earth elements can be added as auxiliary agents, such as Ce2S3, YCl3 and other substances, which can improve the ionic conductivity and air stability of sulfide solid electrolyte.

[0035] The solvent includes tetrahydrofuran, DME, ACN, ethyl acetate and ethanol, mainly organic solvents, and liquids containing water are avoided as solvents.

[0036] Solvent evaporation conditions include:

[0037] 150℃~200℃ flowing hot air flow, hot air flow rate is 250L / h, hot air pressure is 10bar~20bar, hot air flow is inert gas or carbon dioxide;

[0038] The mixed slurry is stirred while evaporating until a solid solute is obtained.

[0039] The working conditions of the high-energy ball mill include a rotation speed of 60 to 300 rpm, a ball milling time of 60 to 120 h, and a ball-to-material ratio of 5 to 30:1.

[0040] The high temperature constant temperature treatment temperature is 550° C., the constant temperature treatment time is 7 to 10 hours, and the heating and cooling rate is 0.5° C. / min.

[0041] A sulfide solid electrolyte is prepared by the above-mentioned preparation method, and the D50 of the sulfide solid electrolyte is 0.01-5 μm.

[0042] The invention relates to an application of a sulfide solid electrolyte in liquid lithium-ion batteries and solid lithium-ion batteries.

[0043] Example 2:

[0044] See also Figure 1 See Figure 1 As shown, a method for preparing a sulfide solid electrolyte comprises:

[0045] The Li2S, P2S5, auxiliary agent and solvent are mixed uniformly to prepare a mixed slurry;

[0046] After the mixed slurry is stirred evenly, the solvent is evaporated at high temperature to obtain a solid solute;

[0047] placing the solid solute in a high-energy ball mill for processing to obtain a powder mixture;

[0048] The powder mixture is treated at high temperature and constant temperature, and the sulfide solid electrolyte is obtained after cooling;

[0049] The foregoing steps are all carried out in a sealed inert gas atmosphere.

[0050] As can be seen from the above, the raw materials, auxiliary agents and solvents are first mixed to prepare a mixed slurry, so that the raw materials and auxiliary agents and other components can be fully mixed, facilitating the full reaction between the materials in the subsequent reaction. Then the solvent is evaporated at high temperature, leaving a solid solute, and the solid solute is treated using a high-energy ball mill, so that the raw materials and auxiliary agents are mixed and reacted to form a powder mixture. Finally, the powder mixture is treated at high temperature and high pressure, and the sulfide solid electrolyte is obtained after cooling. The combination of liquid and solid treatment methods not only effectively improves the production capacity of the sulfide solid electrolyte, but also effectively improves the ionic conductivity of the sulfide solid electrolyte, improves the performance of the battery prepared using the sulfide solid electrolyte, and the addition of auxiliary agents can inhibit the growth of lithium dendrites and improve the chemical stability and environmental stability of the sulfide solid electrolyte.

[0051] The auxiliary agent includes LiCl and Sc2O3, and the mixing ratio of Li2S, P2S5, LiCl and Sc2O3 is 2.54:0.48:1:0.02, and the product generated by the reaction is a series of Li 6+2x P 1-x Sc x S 5-1.5x O 1.5x Cl sulfide solid electrolyte, by introducing different elements to improve the ionic conductivity and air stability of the sulfide electrolyte, in addition, some other rare earth elements can also be used as auxiliary agents for addition, such as Ce2S3, YCl3 and other substances, which can improve the ionic conductivity and air stability of the sulfide solid electrolyte.

[0052] The solvent includes tetrahydrofuran, DME, ACN, ethyl acetate and ethanol, which are mainly organic solvents to avoid using liquid with water as a solvent.

[0053] The solvent evaporation conditions include:

[0054] The hot gas flow is 250L / h, the hot gas pressure is 10bar, and the hot gas is inert gas or carbon dioxide;

[0055] The mixed slurry is stirred while evaporating until the solid solute is obtained.

[0056] The working conditions of the high-energy ball mill include a rotation speed of 60rpm, a ball milling time of 60h and a ball-to-material ratio of 5:1.

[0057] The high-temperature constant temperature treatment temperature is 550 DEG C, the constant temperature treatment time is 7h, and the heating and cooling rate is 0.5 DEG C / min.

[0058] A sulfide solid electrolyte prepared by the preparation method, wherein the D50 of the sulfide solid electrolyte is 1 mu m.

[0059] Application of a sulfide solid electrolyte in a liquid lithium ion battery and a solid-state lithium ion battery.

[0060] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0061] In the drawings of the embodiments of the present application, only the structures related to the embodiments of the present application are involved, and other structures can refer to the general design. In the case of no conflict, the same embodiment and different embodiments of the present application can be combined with each other.

Claims

1. A method for preparing a sulfide solid electrolyte, characterized in that: include: The Li2S, P2S5, auxiliary agent and solvent are mixed uniformly to prepare a mixed slurry; After the mixed slurry is stirred evenly, the solvent is evaporated at high temperature to obtain a solid solute; placing the solid solute in a high-energy ball mill for processing to obtain a powder mixture; The powder mixture is treated at a high temperature and constant temperature, and a sulfide solid electrolyte is obtained after cooling; The above steps are all carried out in a sealed inert gas atmosphere.

2. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The auxiliary agent includes LiCl and Sc2O3, and the mixing ratio of Li2S, P2S5, LiCl and Sc2O3 is 2.54:0.48:1:0.

02.

3. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The solvents include tetrahydrofuran, DME, ACN, ethyl acetate and ethanol.

4. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: Solvent evaporation conditions include: 150℃~200℃ flowing hot air flow, hot air flow rate is 250L / h, hot air pressure is 10bar~20bar, hot air flow is inert gas or carbon dioxide; The mixed slurry is stirred while evaporating until a solid solute is obtained.

5. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The working conditions of the high-energy ball mill include a rotation speed of 60 to 300 rpm, a ball milling time of 60 to 120 h, and a ball-to-material ratio of 5 to 30:

1.

6. The method for preparing a sulfide solid electrolyte according to claim 1, wherein: The high temperature constant temperature treatment temperature is 550° C., the constant temperature treatment time is 7 to 10 hours, and the heating and cooling rate is 0.5° C. / min.

7. A sulfide solid electrolyte, characterized in that: The sulfide solid electrolyte is prepared by the preparation method according to any one of claims 1 to 6.

8. A sulfide solid electrolyte according to claim 7, characterized in that: The D50 of the sulfide solid electrolyte is 0.01 to 5 μm.

9. Use of the sulfide solid electrolyte prepared by the preparation method according to any one of claims 1 to 6 in liquid lithium-ion batteries and solid lithium-ion batteries.

Images