Electrolyte, solid-state battery, preparation method of solid-state battery and power-related equipment

Abstract

The invention provides an electrolyte, a solid-state battery, a preparation method of the solid-state battery and power-related equipment, and relates to the technical field of solid-state batteries. The preparation method of the electrolyte comprises the following steps: mixing lithium hexafluorophosphate, lithium bis (trifluoromethane sulfonimide), ethylene carbonate and diethyl carbonate to obtain a first mixture; and adding a polypyrrole glue solution and 1-propyl pyridine bis (trifluoromethylsulfonyl) imide salt into the first mixed material to obtain the electrolyte. According to the preparation method of the electrolyte provided by the invention, by reasonably selecting and combining multiple key components, the improvement of ion conduction efficiency, the enhancement of interface stability, the optimization of fast charging performance and the widening of a multiplying power window are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular, to an electrolyte, a solid-state battery, a preparation method thereof, and an electricity-related device. Background Art

[0002] As an emerging energy storage technology, solid-state batteries have received extensive attention in recent years. Compared with traditional liquid lithium-ion batteries, solid-state batteries use solid electrolytes to replace liquid electrolytes, thereby significantly improving the safety performance of the batteries and promising to break through the energy density bottleneck of liquid batteries. The non-flammability and low volatility of solid electrolytes make them show higher stability under high-temperature and high-energy density conditions, providing a safer and more efficient energy solution for fields such as electric vehicles, energy storage systems, and portable electronic devices.

[0003] In the existing solid-state battery technology, although significant progress has been made in the safety of solid electrolyte materials, many challenges still exist in practical applications. Currently, the cycle life of solid-state batteries is generally short and cannot meet the requirements of long-term use. In addition, the ionic conductivity of solid electrolytes is relatively low, especially at room temperature, which limits the charge and discharge rate and overall performance of the batteries. The lack of fast charging performance is one of the important factors restricting the commercialization process of solid-state batteries because fast charging ability is crucial for applications such as electric vehicles.

[0004] The defects of these existing technologies pose significant obstacles to the wide application of solid-state batteries. The insufficient cycle life means that the batteries need to be replaced more frequently, increasing the use cost and resource consumption. The low ionic conductivity causes the performance of the batteries to decline during high-rate charge and discharge, and the advantages of their high energy density cannot be fully utilized. The lack of fast charging performance limits the application of solid-state batteries in scenarios where fast charging is required, such as fast charging stations for electric vehicles. These technical bottlenecks not only affect the market competitiveness of solid-state batteries but also hinder their further promotion in the new energy field.

[0005] In summary, the deficiencies of the existing solid-state battery technology in terms of cycle life, ionic conductivity, and fast charging performance severely limit its potential for commercialization and wide application. Solving these key problems is of great significance for promoting the development of solid-state battery technology and meeting the growing energy demand.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide an electrolyte, a solid-state battery, a preparation method thereof, and an electricity-related device, and the electrolyte realizes the improvement of ion conduction efficiency, the enhancement of interfacial stability, the optimization of fast charging performance, and the broadening of the rate window.

[0008] To achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0009] In a first aspect, the present invention provides a method for preparing an electrolyte, comprising:

[0010] Mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate and diethyl carbonate to obtain a first mixture;

[0011] Adding polypyrrole colloidal solution and 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt to the first mixture to obtain an electrolyte.

[0012] In an optional embodiment, the chemical structural formula of polypyrrole in the polypyrrole colloidal solution is:

[0013]

[0014] In an optional embodiment, the molecular weight of the polypyrrole is not less than 200,000;

[0015] In an optional embodiment, the viscosity of the polypyrrole colloidal solution is 3000 mPa·s to 8000 mPa·s;

[0016] In an optional embodiment, the method for preparing the polypyrrole colloidal solution comprises:

[0017] Preparing an acidic solution;

[0018] Adding pyrrole to the acidic solution for an oxidation polymerization reaction, and separating to obtain the polypyrrole colloidal solution;

[0019] In an optional embodiment, the method for preparing the acidic solution is: using oxalic acid to prepare the acidic solution from hydrogen peroxide;

[0020] In an optional embodiment, the pH of the acidic solution is 2.5.

[0021] In an optional embodiment, adding pyrrole to the acidic solution for an oxidation polymerization reaction includes:

[0022] Adding pyrrole to the acidic solution for a first stirring treatment to conduct an oxidation polymerization reaction on pyrrole;

[0023] In an optional embodiment, the first stirring treatment process includes at least one of the following treatment conditions:

[0024] A. Sealing and controlling the oxygen and water content to be lower than 0.5 ppm;

[0025] B. The temperature is 32°C to 38°C;

[0026] C. The stirring speed is 300 rpm / min;

[0027] D. The stirring time is not less than 48 hours.

[0028] In an alternative embodiment, in the first mixture, the addition amounts of the respective components are as follows:

[0029] Lithium hexafluorophosphate: 0.03 mol to 1.00 mol;

[0030] Lithium bis(trifluoromethanesulfonyl)imide: 0.05 mol to 1.00 mol;

[0031] A mixture of ethylene carbonate and diethyl carbonate: 10 mL to 1000 mL; the ratio of ethylene carbonate to diethyl carbonate in the mixture is 3:7.

[0032] In an alternative embodiment, mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate and diethyl carbonate to obtain the first mixture includes:

[0033] After mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate and diethyl carbonate, performing a second stirring treatment to obtain the first mixture;

[0034] In an alternative embodiment, the second stirring treatment process includes at least one of the following treatment conditions:

[0035] A. Sealing and controlling the oxygen and water content to be less than 0.5 ppm;

[0036] B. The temperature is 22°C to 28°C;

[0037] C. The stirring speed is 1000 rpm / min;

[0038] D. The stirring time is not less than 15 minutes.

[0039] In an alternative embodiment, adding polypyrrole colloidal solution and 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt to the first mixture to obtain the electrolyte includes:

[0040] Adding the polypyrrole colloidal solution to the first mixture and performing a third stirring treatment to obtain a second mixture;

[0041] Adding 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt to the second mixture and performing a fourth stirring treatment to obtain the electrolyte;

[0042] In an alternative embodiment, the stirring conditions of the third stirring treatment include at least one of the following conditions:

[0043] A. The temperature is 22°C to 28°C;

[0044] B. The stirring speed is 1000 rpm / min;

[0045] C. The stirring time is not less than 10 minutes;

[0046] In an alternative embodiment, the stirring conditions for the fourth stirring treatment include at least one of the following conditions:

[0047] A. The stirring speed is 1000 rpm / min;

[0048] B. The stirring time is not less than 15 minutes;

[0049] In an alternative embodiment, the chemical structural formula of the 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt is:

[0050]

[0051] In a second aspect, the present invention provides an electrolyte solution prepared by the method for preparing an electrolyte solution according to any one of the foregoing embodiments.

[0052] In a third aspect, the present invention provides a method for preparing a solid-state battery, comprising:

[0053] Adding a solid electrolyte to PVDF for mixing, and performing a pressing treatment to obtain a solid electrolyte membrane;

[0054] Coating the electrolyte solution according to the foregoing embodiment on the solid electrolyte membrane to obtain a composite membrane with a coating layer, and preparing a solid-state battery based on the composite membrane;

[0055] In an alternative embodiment, the solid electrolyte includes at least one of LATP, LLZO, and LLTO;

[0056] In an alternative embodiment, the addition ratio of the solid electrolyte accounts for 0.5% to 5% of the total ratio of the solid electrolyte and PVDF;

[0057] In an alternative embodiment, the specification of the electrolyte solution coated on the surface of the solid electrolyte membrane is 0.3 mg / cm 3 ~3 mg / cm 3 .

[0058] In a fourth aspect, the present invention provides a solid-state battery prepared by the method for preparing a solid-state battery according to the foregoing embodiment.

[0059] In a fifth aspect, the present invention provides an electricity-related device including the solid-state battery according to the foregoing embodiment.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] In the present invention, by using lithium hexafluorophosphate (LiPF 6 ) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as lithium salts and mixing them with ethylene carbonate (EC) and diethyl carbonate (DEC), the formed basic electrolyte system has good ionic conduction performance. The synergistic effect of these two lithium salts can provide sufficient lithium ions and at the same time reduce the viscosity of the electrolyte, thereby increasing the transference number and conduction efficiency of lithium ions. In addition, the mixed solvent system of ethylene carbonate and diethyl carbonate can further optimize the electrochemical window and ion transport performance of the electrolyte.

[0062] Adding polypyrrole colloidal solution to the basic mixture brings remarkable interfacial stability to the electrolyte. Polypyrrole is rich in nitrogen-containing functional groups, and these functional groups can form a stable coordination structure with lithium ions, thereby forming a highly stable interfacial layer at the interface between the electrode and the electrolyte. This interfacial layer can effectively inhibit the reduction reaction of the solid electrolyte and reduce the occurrence of interfacial side reactions, thereby significantly improving the cycle stability and service life of the battery.

[0063] Adding 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt (BPYNTF 2 ) further optimizes the performance of the electrolyte. BPYNTF 2 , as an ionic liquid, has strong ionization ability and electrochemical stability. It can form an electron delocalization structure at the interface, thereby realizing a continuous ion transport channel and significantly reducing the interfacial impedance. This property is crucial for improving the fast charging performance of the battery and can achieve fast charging while ensuring the safety of the battery.

[0064] By the synergistic effect of the above components, the prepared electrolyte can significantly broaden the rate window of the battery. Experiments show that the rate window of the solid-state battery using this electrolyte can be broadened from 0.5C to 2C at room temperature. This means that the battery can work stably at a higher charge-discharge rate, meeting the requirements of high-rate charge-discharge in application scenarios such as electric vehicles, while maintaining good electrochemical performance.

[0065] In summary, the electrolyte preparation method provided by the present invention realizes the improvement of ionic conduction efficiency, the enhancement of interfacial stability, the optimization of fast charging performance, and the broadening of the rate window by reasonably selecting and combining various key components. These beneficial effects work together to significantly improve the overall performance of the solid-state battery and provide important technical support for the commercial application of solid-state batteries. Description of the Drawings

[0066] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0067] Figure 1 It is a schematic flow chart of the preparation method of the electrolyte in the embodiment of the present application;

[0068] Figure 2 It is the synthesis reaction formula of polypyrrole in the embodiment of the present application;

[0069] Figure 3 It is the electrochemical impedance spectroscopy (EIS) diagram in the comparative test experiment of the present application. Specific Embodiments

[0070] The following will describe the implementation plan of the present invention in detail in combination with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. Those reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0071] Reference Figure 1 , in the embodiment of the present application, a preparation method of an electrolyte is provided, including:

[0072] Step S1, mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate and diethyl carbonate to obtain a first mixture.

[0073] This step is the basic stage of electrolyte preparation. By mixing lithium hexafluorophosphate (LiPF 6 ), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), ethylene carbonate (EC) and diethyl carbonate (DEC) in a certain proportion to form a uniform first mixture, a mixed solution containing two lithium salts and two carbonate solvents is obtained. This mixed solution has the basic composition framework of the electrolyte and provides a basis for adding other components later.

[0074] Lithium hexafluorophosphate and lithium bis(trifluoromethanesulfonyl)imide as lithium salts can provide sufficient lithium ions, and their synergistic effect can optimize the transference number and conduction efficiency of lithium ions. The mixed solvent system of ethylene carbonate and diethyl carbonate can provide good electrochemical stability, while optimizing the viscosity and electrochemical window of the electrolyte. In addition, this mixed system is compatible with the existing lithium-ion battery production process, facilitating subsequent industrial applications.

[0075] Step S2: Add polypyrrole colloidal solution and 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt to the first mixture to obtain an electrolyte solution.

[0076] The above steps are based on the first mixture and further introduce polypyrrole colloidal solution and 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt (BPYNTF 2 ), to optimize the performance of the electrolyte solution. The obtained electrolyte solution not only has the ion conductivity of the basic mixture, but also further improves the interface stability and fast charging performance through the introduction of polypyrrole and BPYNTF 2 .

[0077] Polypyrrole is rich in nitrogen-containing functional groups, which can form a stable interface layer at the electrode / electrolyte interface, inhibit the reduction reaction of the solid electrolyte, and reduce interface side reactions. BPYNTF 2 , as an ionic liquid, has strong ionization ability, can form an electron delocalized structure at the interface, realize a continuous ion transport channel, significantly reduce the interface impedance, and thus improve the fast charging performance.

[0078] Experiments show that the rate window of the solid-state battery using this electrolyte solution can be widened from 0.5C to 2C at room temperature.

[0079] Through the above two steps, the prepared electrolyte solution has high ion conductivity, interface stability and fast charging performance, and can significantly improve the overall performance of the solid-state battery.

[0080] In some embodiments, the chemical structural formula of polypyrrole in the polypyrrole colloidal solution is:

[0081]

[0082] The chemical structural formula of polypyrrole (PPy) is a polymer with repeating units, and its basic unit is pyrrole (C 4 H 5 N), which forms a polymer chain through polymerization. As a result, polypyrrole has good electrical conductivity and electrochemical properties, is suitable for use in battery electrolyte solutions, and provides an ion conduction path.

[0083] The advantages of adding polypyrrole include: good electrical conductivity, which can improve the ion conduction efficiency of the electrolyte solution; high chemical stability, which can remain stable during the charge and discharge process of the battery, and is rich in nitrogen-containing functional groups, which can form a stable coordination structure with lithium ions.

[0084] In some embodiments, the molecular weight of the polypyrrole is not less than 200,000.

[0085] In some embodiments, the viscosity of the polypyrrole glue solution is 3000 mPa·s to 8000 mPa·s. For example, the viscosity can be 3000 mPa·s, 4000 mPa·s, 5000 mPa·s, 6000 mPa·s, 7000 mPa·s, 8000 mPa·s, and so on.

[0086] In some embodiments, the method for preparing the polypyrrole glue solution includes:

[0087] (1) Prepare an acidic solution; specifically, the method for preparing the acidic solution can be: using oxalic acid (C 2 H 2 O 4 ) to prepare the hydrogen peroxide (H 2 O 2 ) into the acidic solution; wherein, the pH of the acidic solution can be 2.5.

[0088] (2) Add pyrrole to the acidic solution for oxidative polymerization reaction, and obtain the polypyrrole glue solution after separation.

[0089] In the above steps, the preparation of the polypyrrole glue solution includes preparing an acidic solution, adding pyrrole monomer for oxidative polymerization reaction, and obtaining the polypyrrole glue solution by separation. Thus, the obtained polypyrrole glue solution has high molecular weight, appropriate viscosity and good conductivity, and is suitable for the preparation of electrolytes. This method has a simple preparation process, low cost, and is suitable for large-scale production; the conductivity and stability of polypyrrole can significantly improve the performance of electrolytes; by controlling the reaction conditions, the molecular weight and viscosity of polypyrrole can be adjusted.

[0090] For the above oxidative polymerization reaction, its reaction formula can be as Figure 2 shown. Pyrrole is oxidized by hydrogen peroxide under acidic conditions and gradually polymerizes to form polypyrrole. Polypyrrole is a polymer with good conductivity and is commonly used in electrochemical applications. For example, it can be to use C 2 H 2 O 4 to adjust 1.05 mol of hydrogen peroxide H2O2 into an acidic solution with a pH of 2.5.

[0091] In some embodiments, adding pyrrole to the acidic solution for oxidative polymerization reaction includes: adding pyrrole to the acidic solution for the first stirring treatment to carry out the oxidative polymerization reaction on pyrrole.

[0092] In the above, separating to obtain the polypyrrole glue solution can be, after the reaction is completed, putting the product into a centrifuge for separation to remove reaction by-products (such as H 2 O and CO 2) The resulting polypyrrole colloidal solution has a molecular weight ≥ 200,000 and a viscosity of 3,000 mPa·s to 8,000 mPa·s.

[0093] In some embodiments, the first stirring treatment process includes at least one of the following treatment conditions:

[0094] A. Sealed and controlled with oxygen and water content below 0.5 ppm;

[0095] B. The temperature is 32°C to 38°C; for example, it can be 32°C, 34°C, 36°C, 38°C, etc.

[0096] C. The stirring speed is 300 rpm / min;

[0097] D. The stirring time is not less than 48 hours.

[0098] In some embodiments, in the first mixture, the addition amounts of each component are as follows:

[0099] Lithium hexafluorophosphate 0.03 mol to 1.00 mol; for example, it can be 0.03 mol, 0.05 mol, 0.08, 0.01 mol, 0.50 mol, 0.80 mol, 1.00 mol, etc.

[0100] Lithium bis(trifluoromethanesulfonyl)imide 0.05 mol to 1.00 mol; for example, it can be 0.05 mol, 0.08, 0.01 mol, 0.50 mol, 0.80 mol, 1.00 mol, etc.

[0101] A mixture of ethylene carbonate and diethyl carbonate 10 mL to 1000 mL; the ratio of ethylene carbonate to diethyl carbonate in the mixture is 3:7. For example, the amount of the mixture can be 10 mL, 50 mL, 100 mL, 200 mL, 500 mL, 800 mL, 1000 mL, etc.

[0102] In some embodiments, in step S1, mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate and diethyl carbonate to obtain a first mixture includes: after mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate and diethyl carbonate, performing a second stirring treatment to obtain the first mixture.

[0103] Specifically, lithium hexafluorophosphate (LiPF 6) Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), ethylene carbonate (EC), and diethyl carbonate (DEC) are mixed in a certain proportion to form a basic electrolyte mixture. The above four components can be added to a reaction vessel in proportion and stirred thoroughly to make them fully mixed. As a result, a uniform electrolyte mixture is obtained, in which the lithium salt provides lithium ions, and the carbonate solvents provide good ionic conductivity and electrochemical stability.

[0104] LiPF 6 and LiTFSI act synergistically to provide sufficient lithium ions and optimize the transference number of ions. The mixed solvent system of ethylene carbonate and diethyl carbonate has good electrochemical stability and can support high-voltage operation. This mixed system is compatible with the existing lithium-ion battery production process and is convenient for subsequent processing.

[0105] In some embodiments, the second stirring treatment process includes at least one of the following treatment conditions:

[0106] A. Seal and control the oxygen and water content to be less than 0.5 ppm;

[0107] B. The temperature is 22°C to 28°C;

[0108] C. The stirring speed is 1000 rpm / min;

[0109] D. The stirring time is not less than 15 minutes.

[0110] Specifically, first, an EC and DEC mixed solvent can be prepared, such as preparing 100 mL of the mixed solvent (30 mL EC + 70 mL DEC) according to a 3:7 ratio. Then, LiPF 6 : 0.1 mol and LiTFSI: 0.1 mol are taken according to the molar mass. LiPF 6 and LiTFSI can be added to the EC and DEC mixed solvent. The operation can be carried out in a glove box to ensure that the oxygen and water content is less than 0.5 ppm.

[0111] The mixture can be put into a stirring kettle and sealed. Set the stirring speed to 1000 rpm / min and the temperature to 25°C. Stir for not less than 15 minutes to ensure that all components are fully mixed. A uniform and stable basic electrolyte mixture is obtained, which serves as the substrate for subsequent addition of polypyrrole colloidal solution and BPYNTF 2 .

[0112] In some embodiments, in step S2, adding a polypyrrole colloidal solution and 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt to the first mixture to obtain an electrolyte includes:

[0113] Step S21: Add the polypyrrole colloidal solution to the first mixture and perform a third stirring process to obtain a second mixture. Among them, the stirring conditions of the third stirring process include at least one of the following conditions: A. The temperature is 22°C to 28°C. For example, it can be 22°C, 24°C, 26°C, 28°C, etc. B. The stirring speed is 1000 rpm / min. C. The stirring time is not less than 10 minutes.

[0114] In the above steps, add the polypyrrole colloidal solution to the already prepared first mixture (containing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, ethylene carbonate, and diethyl carbonate), and perform a stirring process to ensure that the polypyrrole colloidal solution is evenly dispersed in the mixture.

[0115] Polypyrrole is rich in nitrogen-containing functional groups, which can form a stable interfacial layer at the electrode / electrolyte interface, inhibit the reduction of the solid electrolyte, and reduce interfacial side reactions. The addition of polypyrrole provides an additional ion conduction path for the electrolyte and improves the conductivity of the electrolyte. Through the stirring process, ensure that the polypyrrole colloidal solution is evenly distributed in the mixture to avoid too high or too low local concentration.

[0116] Specifically, the third stirring process can be carried out by a stirring device. For example, it can be a high-shear mixer, a magnetic stirrer, etc. It can be carried out in a glove box, controlling the oxygen and water content to be lower than 0.5 ppm to prevent impurities from affecting the electrolyte.

[0117] Step S22: Add 1-propylpyridinium bis(trifluoromethylsulfonyl)imide to the second mixture and perform a fourth stirring process to obtain the electrolyte. The chemical structural formula of 1-propylpyridinium bis(trifluoromethylsulfonyl)imide is:

[0118] Among them, the stirring conditions of the fourth stirring process include at least one of the following conditions:

[0119] A. The stirring speed is 1000 rpm / min;

[0120] B. The stirring time is not less than 15 minutes.

[0121] In the above steps, add 1-propylpyridinium bis(trifluoromethylsulfonyl)imide (BPYNTF 2 ) to the second mixture and perform a stirring process to obtain the final electrolyte, in which BPYNTF 2 is evenly dispersed in the mixture to form an electrolyte with high ionic conductivity and interfacial stability.

[0122] BPYNTF 2As an ionic liquid, it has strong ionization ability, can form an electron delocalization structure at the interface, realize a continuous ion transport channel, and significantly reduce the interface impedance. BPYNTF 2 It can form an interfacial layer with high mechanical stability and electrochemical stability at the interface, has fast ion transport ability, and further improves the fast charging performance and cycle life of the battery. Through stirring treatment, ensure that BPYNTF 2 is evenly distributed in the electrolyte to avoid too high or too low local concentration.

[0123] The stirring equipment can use a high-shear mixer or a magnetic stirrer. The operation environment can be carried out in a glove box, controlling the oxygen and water content to be lower than 0.5 ppm to prevent impurities from affecting the electrolyte.

[0124] In the embodiments of the present application, an electrolyte is provided, which is prepared by the preparation method of the electrolyte described in any one of the foregoing embodiments.

[0125] In the embodiments of the present application, a preparation method of a solid-state battery is provided, including:

[0126] (1) Add the solid electrolyte to PVDF and mix, and perform tablet pressing to obtain a solid electrolyte membrane. Among them, the solid electrolyte may include at least one of LATP, LLZO, and LLTO; the addition ratio of the solid electrolyte accounts for 0.5% to 5% of the total ratio of the solid electrolyte and PVDF. For example, it can be 0.5%, 1%, 2%, 3%, 4%, 5%, etc.

[0127] (2) Coat the electrolyte described in the foregoing embodiment on the solid electrolyte membrane to obtain a composite membrane with a coating layer, and prepare a solid-state battery based on the composite membrane.

[0128] In some embodiments, the specification of the electrolyte coated on the surface of the solid electrolyte membrane is 0.3 mg / cm 3 ~3 mg / cm 3 . For example, it can be 0.3 mg / cm 3 , 0.5 mg / cm 3 , 0.8 mg / cm 3 , 1 mg / cm 3 , 2 mg / cm 3 , 3 mg / cm 3 etc.

[0129] For the above preparation of the solid-state battery, the solid electrolyte can be added to PVDF according to the ratio, mixed evenly and then pressed into tablets, so as to ensure that the solid electrolyte membrane has good flexibility.

[0130] Then, the electrolyte solution is coated on the solid electrolyte membrane, which can be coated on the surface of the pressed sheet on one side, specifically, it can be coated with 0.3 mg / cm 3 ~3 mg / cm 3 .

[0131] Furthermore, the coated pressed sheet is made into a solid-state battery, making the coating layer contact with the negative electrode, and performing high-temperature and high-pressure infiltration under the conditions of 85 °C and a binding force of 20 Mpa for 6 h.

[0132] In the embodiment of the present application, a solid-state battery is provided, which is prepared by the preparation method of the solid-state battery as described in the foregoing embodiment.

[0133] In the embodiment of the present application, an electric-related device is provided, including the solid-state battery as described in the foregoing embodiment.

[0134] The present invention will be further described below through specific embodiments. However, it should be understood that these embodiments are only used for more detailed description and should not be construed as limiting the present invention in any form.

[0135] Table 1. Raw materials and specific parameter tables in the examples and comparative examples

[0136] Raw material / Parameter Example 1 Example 2 Example 3 Example 4 Comparative Example 1 <![CDATA[LiPF 6 > 0.03 mol 0.1 mol 0.1 mol 0.3 mol / LiTFSI 0.06 mol 0.1 mol 0.2 mol 0.5 mol / EC / DEC 400 mL 400 mL 400 mL 400 mL / Polypyrrole colloidal solution 10 mL 10 mL 0 mL 2 mL / <![CDATA[BPYNTF 2 > 2 2 1 0 / Solid electrolyte LLZO LLZO LLTO LATP LLZO Coating specification of composite membrane <![CDATA[0.3mg / cm 2 > <![CDATA[0.8mg / cm 2 > <![CDATA[2mg / cm 2 > <![CDATA[5mg / cm 2 > 0 (not coated)

[0137] Example 1

[0138] In this embodiment, a solid-state battery was prepared.

[0139] Experimental method: The specific raw materials and parameters refer to Table 1.

[0140] (1) Preparation of polypyrrole colloidal solution: In a reaction tank, oxalic acid (C 2 H 2 O 4 ) was used to modulate 1.05 mol of hydrogen peroxide (H 2 O 2 ) into an acidic solution with a pH of 2.5, and 1 mol of pyrrole was added to the reaction tank containing the acidic solution. This step was carried out in a glove box, controlling the oxygen and water content in the reaction tank to be less than 0.5 ppm. After the feeding was completed, it was sealed and taken out to the reaction kettle for reaction. The stirring conditions were 35 °C ± 3 °C and 300 rpm / min, and the stirring was carried out for 48 h. After the synthesis was completed, it was put into a centrifuge to separate the polymer and the reaction products (H 2 O and CO 2 ) to obtain the polypyrrole colloidal solution.

[0141] (2) Add LiPF 6, LiTFSI, and a mixture of EC / DEC (EC:DEC = 3:7) were added to the reaction tank of the reactor. This step was carried out in a glove box, controlling the oxygen and water content in the reaction tank to be less than 0.5 ppm. After the feeding was completed, the reaction tank was sealed and taken out.

[0142] It was placed in the reactor and stirred. The stirring conditions were 25°C ± 3°C and 1000 rpm / min for 15 min to completely dissolve it.

[0143] (3) After dissolution, polypyrrole colloidal solution was added in the glove box (oxygen and water content less than 0.5 ppm) and stirred evenly. The stirring conditions were 25°C ± 3°C and 1000 rpm / min for 10 min; after mixing, a gel electrolyte was obtained, which was convenient for subsequent coating.

[0144] (4) After mixing, the reactor was placed in the glove box (oxygen and water content less than 0.5 ppm), and then 0.1 - 10 mL of 1-propylpyridinium bis(trifluoromethylsulfonyl)imide salt (BPYNTF 2 ) was added. It was stirred evenly at 1000 rpm / min for 15 min. An electrolyte was obtained.

[0145] (5) The solid electrolyte was added to PVDF, and after mixing evenly, it was pressed into a sheet to obtain a solid electrolyte membrane.

[0146] (6) The solid electrolyte membrane was fabricated into a solid-state battery, with the coating layer in contact with the negative electrode. High-temperature and high-pressure infiltration was carried out under the conditions of 85°C and a binding force of 20 Mpa for 6 h. Among them, the main cathode material was 8-series NCM, the proportion of the active material in the cathode system was 97%, PVDF accounted for 1.5%, and CNT + carbon black accounted for 1.5% in total. The single-sided areal density was 320 g / m 2 , and the compaction density was 3.65 g / cc; the negative electrode was a lithium foil with a thickness of 35 μm; a 1 Ah soft-pack battery was made.

[0147] Example 2

[0148] In this example, a solid-state battery was prepared.

[0149] Experimental method:

[0150] It was basically the same as the method in Example 1, and the specific raw materials and parameters were referred to Table 1 for differences.

[0151] Example 3

[0152] In this example, a solid-state battery was prepared.

[0153] Experimental method:

[0154] It was basically the same as the method in Example 1, and the specific raw materials and parameters were referred to Table 1 for differences.

[0155] Example 4

[0156] In this example, a solid-state battery was prepared.

[0157] Experimental method:

[0158] It was basically the same as the method in Example 1, with the specific raw materials and parameters referring to Table 1 for differences.

[0159] Comparative Example 1

[0160] In this comparative example, a solid-state battery was prepared.

[0161] Experimental method:

[0162] It was basically the same as the method in Example 1, except that:

[0163] An uncoated solid electrolyte tablet was used to prepare a solid-state battery. The process conditions, cathode and anode materials, etc. in other steps were basically the same as those in the experimental group.

[0164] Among them, the raw materials and parameters refer to Table 1. In this comparative example, the uncoated solid electrolyte film pressed in Example 1 was used to prepare a solid-state battery, and high-temperature and high-pressure shaping was carried out under the conditions of 85 °C and a binding force of 20 Mpa for 6 h. Among them, the main cathode material was 8-series NCM, the proportion of the active substance in the cathode system was 97%, PVDF accounted for 1.5%, and CNT + carbon black together accounted for 1.5%; the single-sided areal density was 320 g / m 2 , and the compaction was 3.65 g / cc; the anode was a lithium foil with a thickness of 35 μm; a 1 Ah soft-pack battery was made.

[0165] Testing experiments:

[0166] Testing method:

[0167] The electrical performance of the battery cells of the solid-state batteries prepared in the examples and comparative examples was tested. The test results refer to the data in Table 2 and Figure 3 .

[0168] Table 2. Test experimental result table

[0169]

[0170] (1) Electrochemical performance test:

[0171] Testing method: Electrochemical impedance spectroscopy (EIS) was used for testing.

[0172] Testing purpose: To evaluate the influence of the electrolyte on the internal resistance and charge transfer efficiency of the battery.

[0173] Testing results: Refer to Figure 3, the ohmic impedance and charge transfer impedance of the experimental group were significantly lower than those of the comparative example, indicating that the electrolyte of the experimental group had better ionic conductivity and electrode reaction kinetics performance.

[0174] (2) Cycle life test

[0175] Test method: Through charge-discharge cycle testing, record the cycle number and capacity retention rate of the battery under certain conditions.

[0176] Test purpose: Evaluate the influence of the electrolyte on the cycle stability and life of the battery.

[0177] (3) Rate performance test

[0178] Test method: Conduct charge-discharge tests at different rates (such as 0.2C, 0.5C, 1C, 2C, etc.), and record the discharge capacity and voltage plateau of the battery.

[0179] Test purpose: Evaluate the influence of the electrolyte on the fast charging performance and high-rate charge-discharge ability of the battery.

[0180] Test results: The normal temperature rate window of the experimental group battery was widened from 0.5C to 2C, indicating that the electrolyte of the experimental group significantly improved the fast charging performance and rate performance of the battery.

[0181] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an electrolyte, characterized in that: include: Mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl imide), ethylene carbonate and diethyl carbonate to obtain a first mixed material; Adding polypyrrole colloid and 1-propylpyridine bis(trifluoromethylsulfonyl)imide salt into the first mixed material to obtain an electrolyte.

2. The method for preparing an electrolyte according to claim 1, characterized in that: The chemical structural formula of polypyrrole in the polypyrrole colloid is: Preferably, the molecular weight of the polypyrrole is not less than 200,000; Preferably, the viscosity of the polypyrrole gel is 3000mPa·s to 8000mPa·s; Preferably, the method for preparing the polypyrrole gel comprises: An acidic solution is prepared; Adding pyrrole to the acidic solution to carry out oxidative polymerization reaction, and obtaining the polypyrrole gel after separation; Preferably, the acidic solution is prepared by: preparing hydrogen peroxide into the acidic solution using oxalic acid; Preferably, the pH of the acidic solution is 2.

5.

3. The method for preparing the electrolyte according to claim 2, characterized in that: The step of adding pyrrole to the acidic solution to carry out an oxidative polymerization reaction comprises: adding pyrrole into the acidic solution and performing a first stirring treatment to perform an oxidative polymerization reaction on the pyrrole; Preferably, the first stirring process includes at least one of the following processing conditions: A. Seal and control the oxygen and water content to less than 0.5ppm; B. Temperature is 32℃~38℃; C. Stirring speed is 300 rpm / min; D. The mixing time is not less than 48 hours.

4. The method for preparing the electrolyte according to claim 1, characterized in that: In the first mixture, the addition amount of each component is respectively: Lithium hexafluorophosphate 0.03 mol~1.00 mol; Lithium bis(trifluoromethanesulfonyl)imide 0.05 mol~1.00 mol; 10 mL to 1000 mL of a mixture of ethylene carbonate and diethyl carbonate; the ratio of ethylene carbonate to diethyl carbonate in the mixture is 3:

7.

5. The method for preparing an electrolyte according to claim 1, characterized in that: The method comprises mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl imide), ethylene carbonate and diethyl carbonate to obtain a first mixed material, comprising: After mixing lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl imide), ethylene carbonate and diethyl carbonate, performing a second stirring treatment to obtain the first mixed material; Preferably, the second stirring process includes at least one of the following processing conditions: A. Seal and control the oxygen and water content to less than 0.5ppm; B. Temperature is 22℃~28℃; C. Stirring speed is 1000 rpm / min; D. The stirring time is not less than 15 minutes.

6. The method for preparing the electrolyte according to claim 1, characterized in that: The step of adding polypyrrole gel and 1-propylpyridine bis(trifluoromethylsulfonyl)imide salt to the first mixed material to obtain an electrolyte comprises: Adding the polypyrrole gel solution to the first mixed material, and performing a third stirring process to obtain a second mixed material; adding 1-propylpyridine bis(trifluoromethylsulfonyl)imide salt to the second mixed material and performing a fourth stirring treatment to obtain the electrolyte; Preferably, the stirring conditions of the third stirring process include at least one of the following conditions: A. The temperature is 22℃~28℃; B. Stirring speed is 1000 rpm / min; C. The stirring time is not less than 10 minutes; Preferably, the stirring conditions of the fourth stirring process include at least one of the following conditions: A. Stirring speed is 1000 rpm / min; B. The stirring time is not less than 15 minutes; Preferably, the chemical structural formula of the 1-propylpyridine bis(trifluoromethylsulfonyl)imide salt is:

7. An electrolyte, characterized in that: The electrolyte is prepared by the method for preparing the electrolyte as described in any one of claims 1 to 6.

8. A method for preparing a solid-state battery, characterized in that: include: The solid electrolyte is added into PVDF for mixing, and then pressed into sheets to obtain a solid electrolyte membrane. Applying the electrolyte as claimed in claim 7 to the solid electrolyte membrane to obtain a composite membrane having a coating layer, and preparing a solid-state battery based on the composite membrane; Preferably, the solid electrolyte comprises at least one of LATP, LLZO and LLTO; Preferably, the addition ratio of the solid electrolyte accounts for 0.5% to 5% of the total ratio of the solid electrolyte and PVDF; Preferably, the specification of the electrolyte coated on the surface of the solid electrolyte membrane is 0.3 mg / cm 3 ~3mg / cm 3 .

9. A solid-state battery, characterized in that: It is prepared by the method for preparing a solid-state battery as described in claim 8.

10. An electrical equipment, characterized in that: Comprising the solid-state battery as claimed in claim 9.

Images