Sulfide composite electrolyte and preparation method thereof

Abstract

The invention discloses a sulfide composite electrolyte and a preparation method thereof, and the preparation method comprises the following steps: mixing oxide electrolyte coarse powder with a preset solvent to obtain an initial mixed solution; pouring the initial mixed solution into a sand mill, and carrying out sanding treatment at a preset temperature to obtain oxide electrolyte slurry; adding a preset solvent and sulfide electrolyte coarse powder into the electrolyte slurry, and continuing sanding treatment to obtain sulfide electrolyte slurry; and drying the sulfide electrolyte slurry to obtain the sulfide composite electrolyte. The oxide electrolyte coarse powder is refined into nano-particles in one pot, the nano-particles directly and uniformly coat the surface of the sulfide electrolyte, the preparation process is simple and efficient, and the sulfide composite electrolyte with high ionic conductivity and low electronic conductivity can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a sulfide composite electrolyte and a preparation method thereof. BACKGROUND

[0002] In order to alleviate environmental and energy pressure, lithium secondary batteries are widely used in 3C digital, automobile, energy storage and other fields due to their high energy density, wide operating temperature range, environmental friendliness and other advantages. However, the traditional lithium ion battery uses liquid electrolyte composed of organic solvents, which has the risk of easy combustion and easy leakage, resulting in a great safety hazard in the use process.

[0003] All-solid-state batteries have the advantages of high safety and high energy density, and are one of the most promising choices for the next generation of lithium batteries. All-solid-state batteries use non-flammable solid-state electrolytes to replace flammable organic electrolytes to build all-solid-state lithium ion batteries, which is expected to fundamentally solve the risk of battery combustion and improve the safety of the battery. In addition, solid-state electrolytes have good mechanical properties and can inhibit the penetration of lithium dendrites, which is expected to be combined with lithium metal anodes to build high-energy-density solid-state lithium metal battery systems. However, they still face challenges in inhibiting the growth of lithium dendrites and ensuring uniform deposition of lithium metal.

[0004] Recent research results show that the growth of Li dendrites starts from the inside of the sulfide electrolyte, and Li metal is directly deposited in the interfacial gap of the sulfide electrolyte interface, and gradually spreads and grows. The reason for this problem is the neglected electronic conductivity of sulfide solid-state electrolyte. In addition, the high electronic conductivity of sulfide electrolyte will cause electron transfer inside the sulfide all-solid-state battery, resulting in serious self-discharge. However, the self-discharge problem has been ignored.

[0005] The prior art faces many challenges in regulating the ionic conductivity and electronic conductivity of sulfide electrolytes. On the one hand, in the process of improving ionic conductivity, it often leads to the increase of electronic conductivity, increasing the risk of battery self-discharge, such as optimizing the crystal structure to increase the lithium ion channel, which makes the structure more open and disordered, providing more transmission paths for electrons; for example, by introducing impurities or defects to improve ionic conductivity, it will become a capture or scattering center for electrons, increasing the electron conduction path. On the other hand, when reducing electronic conductivity, it will greatly sacrifice ionic conductivity, seriously affecting the charge and discharge effect of the battery, such as adjusting the element ratio to increase the localization of electrons, making it more difficult for electrons to conduct in the crystal, but this change in chemical bonds easily affects the interaction between lithium ions and surrounding atoms, making it more difficult for lithium ions to migrate; for example, forming some interface layers at the electrode / electrolyte interface to reduce electronic conductivity, but often these interface layers have high resistance, which will hinder the transmission of lithium ions between the electrode and the electrolyte. There are few reports of achieving a good balance between the two, and this dilemma also limits the widespread application and performance improvement of sulfide electrolytes in lithium-ion batteries, and an innovative method is needed to break through this technical bottleneck.

[0006] Invention patent CN119650822A discloses a sulfide composite electrolyte and its preparation method and application, by mixing an organic coating agent and an organic solvent, then dispersing oxide nanoparticles therein, extracting and drying the precipitate to obtain an oxide@organic coating agent composite material, and then ball milling with a sulfide electrolyte to obtain the sulfide composite electrolyte, solving the above-mentioned lithium dendrite and self-discharge problems in sulfide full solid-state batteries, but this method has high cost, complicated steps, and the last step of dry ball milling is difficult to uniformly composite, and needs to switch between glove boxes, which is difficult to mass produce. SUMMARY

[0007] The present application provides a sulfide composite electrolyte and its preparation method, which refines oxide electrolyte coarse powder into nanoparticles by one-pot sand milling method, and directly coats the surface of sulfide electrolyte, the preparation method is simple and efficient, and the cost is low, which can avoid the agglomeration problem of oxide electrolyte ultrafine nanoparticle slurry after drying into powder.

[0008] In one aspect, the present application provides a preparation method of a sulfide composite electrolyte, the method comprising: mixing oxide electrolyte coarse powder with a predetermined solvent to obtain an initial mixed solution; pouring the initial mixed solution into a sand mill and performing sand milling treatment at a predetermined temperature to obtain an oxide electrolyte slurry; adding the predetermined solvent and sulfide electrolyte coarse powder to the electrolyte slurry and continuing sand milling treatment to obtain a sulfide electrolyte slurry; drying the sulfide electrolyte slurry to obtain the sulfide composite electrolyte.

[0009] Further, the particle size D100 of the oxide electrolyte coarse powder is ≤ 150 μm; The particle size D50 of the oxide electrolyte slurry is between 100 nm and 150 nm; The particle size of the sulfide electrolyte slurry is between 0.8 μm and 1 μm.

[0010] Further, the solid content of the initial mixture ranges from 1.8% to 2.2%; The mixing mass ratio of the sulfide electrolyte coarse powder to the oxide electrolyte coarse powder is 40:1 to 60:1; The preset temperature is ≤ 30℃; The sanding process uses 0.3 mm zirconia balls.

[0011] Further, the sulfide electrolyte coarse powder and the preset solvent are added to the electrolyte slurry, and the sanding process is continued to obtain a sulfide electrolyte slurry, comprising: The oxide electrolyte slurry is added to the preset solvent and the sulfide electrolyte coarse powder to obtain a mixed slurry; The sanding process is continued at the first preset speed under the preset temperature to obtain a sanded mixed slurry; An additive is added to the sanded mixed slurry, and sanding is carried out at a second preset speed to obtain the sulfide electrolyte slurry; the first preset speed is greater than the second preset speed.

[0012] Further, the solid content of the mixed slurry ranges from 18% to 22%; The mass ratio of the additive to the sulfide electrolyte coarse powder is 0.2% to 0.6%; The first preset speed is 1800 rpm to 2200 rpm, and the second preset speed is 800 rpm to 1200 rpm.

[0013] Further, the initial mixture is poured into a sanding machine and sanding is carried out at a preset temperature to obtain an oxide electrolyte slurry, comprising: The initial mixture is poured into the sanding machine and sanding is carried out at the preset temperature; The particle size of the initial mixture is tested every preset time interval during the sanding process, and the sanding process is stopped when the particle size D50 of the initial mixture is between 100 nm and 150 nm, to obtain the oxide electrolyte slurry.

[0014] Further, the mixing of the oxide electrolyte coarse powder with the preset solvent to obtain an initial mixed solution comprises: The oxide electrolyte coarse powder and the preset solvent are respectively subjected to water removal treatment to obtain water-removed oxide electrolyte coarse powder and water-removed preset solvent, and the water-removed oxide electrolyte coarse powder and the water-removed preset solvent are transferred into a glove box; the glove box is filled with nitrogen atmosphere or argon atmosphere; The water-removed oxide electrolyte coarse powder and the water-removed preset solvent are mixed in the glove box to obtain the initial mixed solution.

[0015] Further, the oxide electrolyte coarse powder is one or more of titanium aluminum lithium phosphate, germanium aluminum lithium phosphate, lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, and lithium lanthanum niobium oxide; The preset solvent is one or more of N-methyl pyrrolidone, isobutyl isobutyrate, dimethyl carbonate, ethylene carbonate, diethylene carbonate, and dimethylbenzene; The additive is one or more of hydrogenated styrene-butadiene block copolymer, polyvinylidene fluoride, polyimide, polyacrylonitrile, polyetherimide, and butyl acetate.

[0016] Further, the sulfide electrolyte coarse powder is one or more of LiGePS, LiPSCl, LiPS, LiPSI, and LiPSBr; The drying treatment is one or more of centrifugal drying, vacuum drying, and heating plate solvent evaporation.

[0017] In another aspect, a sulfide composite electrolyte is provided, which is prepared by the above-mentioned method for preparing a sulfide composite electrolyte.

[0018] The sulfide composite electrolyte and the preparation method thereof provided in the present application have the following technical effects: The application mixes the oxide electrolyte coarse powder with a preset solvent to obtain an initial mixed solution; pours the initial mixed solution into a sand mill, and performs sand milling treatment at a preset temperature to obtain an oxide electrolyte slurry; adds a preset solvent and a sulfide electrolyte coarse powder to the electrolyte slurry, and continues to perform sand milling treatment to obtain a sulfide electrolyte slurry; and performs drying treatment on the sulfide electrolyte slurry to obtain a sulfide composite electrolyte. By using the oxide electrolyte coarse powder as one of the preparation raw materials, the application can avoid the problem of agglomeration of the oxide electrolyte ultra-fine nano slurry after being dried into powder; by the one-pot sand milling refinement method, the oxide electrolyte coarse powder is refined into nanoparticles in one pot and directly coated on the surface of the sulfide electrolyte, the preparation method is simple and efficient, and the cost is relatively low; by controlling the addition amount of each substance and the sand milling parameters, sulfide composite electrolytes of different sizes can be customized, the oxide nanoparticles are uniformly coated on the surface of the sulfide electrolyte, the sulfide composite electrolyte has a regular particle morphology, has high ionic conductivity and low electronic conductivity, can ensure the rapid migration of lithium ions in the battery charging and discharging process, realize high-rate charging and discharging of the battery, and can effectively prevent self-discharge of the battery, improve the energy retention capability and safety of the battery.

[0019] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions and advantages of the embodiments or prior art in the specification, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0021] Figure 1 is a flowchart of a preparation method of a sulfide composite electrolyte provided by the embodiments of the present specification; Figure 2 is a flowchart of preparing an initial mixed solution provided by the embodiments of the present specification; Figure 3 is a flowchart of preparing an oxide electrolyte slurry provided by the embodiments of the present specification; Figure 4 is a flowchart of preparing a sulfide electrolyte slurry provided by the embodiments of the present specification; Figure 5 is a scanning electron microscope image of a sulfide composite electrolyte provided by the embodiments of the present specification. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The following describes a method for preparing a sulfide composite electrolyte according to this application, specifically as follows: Figure 1 As shown, the method may include: S1: Mix the oxide electrolyte powder with a pre-set solvent to obtain an initial mixture; S2: Pour the initial mixture into a sand mill and perform sand milling at a preset temperature to obtain an oxide electrolyte slurry; S3: Add the preset solvent and sulfide electrolyte coarse powder to the electrolyte slurry, and continue to perform sand milling to obtain sulfide electrolyte slurry; S4: The sulfide electrolyte slurry is dried to obtain the sulfide composite electrolyte.

[0024] In this embodiment, oxide electrolyte coarse powder is directly used as one of the raw materials. It is refined into ultrafine nanoparticles by sand milling, and then coated onto the surface of sulfide electrolyte by sand milling to form sulfide nanoscale electrolyte with uniform oxide nanoparticle coating. It is not necessary to use ultrafine oxide electrolyte nanoparticle powder, thus avoiding the agglomeration problem after the oxide electrolyte ultrafine nano slurry is dried into powder.

[0025] In this embodiment, the oxide electrolyte coarse powder, the preset solvent, and the additives are first dehydrated and then transferred to a glove box. The oxide electrolyte coarse powder is then weighed and mixed with the preset solvent, i.e., the refining solvent, to obtain an initial mixture. The initial mixture is then slowly poured into a sand mill, and the temperature is controlled. Sand milling is performed at a preset temperature to perform preliminary refining and obtain a uniformly dispersed oxide electrolyte slurry. Then, a preset solvent and coarse sulfide electrolyte powder are added, and the mixture is further milled. After milling for a period of time, additives are added and milled at low speed to ensure that oxide nanoparticles are uniformly coated on the surface of the sulfide electrolyte, resulting in a nano-sized sulfide electrolyte slurry. The nano-sized sulfide electrolyte slurry is then dried to obtain a sulfide composite electrolyte. This sulfide composite electrolyte has oxide nanoparticles uniformly coated on its surface, with regular particle morphology and high ionic conductivity. This ensures rapid migration of lithium ions during battery charging and discharging, enabling high-rate charging and discharging and improving the battery's rate performance. Furthermore, its low electronic conductivity effectively prevents battery self-discharge and enhances the battery's energy retention and safety.

[0026] Further, the particle size D100 of the oxide electrolyte coarse powder is ≤150 μm; The particle size D50 of the particles in the oxide electrolyte slurry is between 100 nm and 150 nm; The particle size of the particles in the sulfide electrolyte slurry is between 0.8 μm and 1 μm.

[0027] In the embodiments of the present application, the oxide electrolyte coarse powder is used as one of the raw materials for preparation. Compared with the ultrafine oxide electrolyte nano powder used in the conventional preparation method, the use of the coarse powder with a larger particle size can effectively avoid the agglomeration problem of the oxide electrolyte ultrafine nano slurry after drying into powder. The particle size D100 of the oxide electrolyte coarse powder is ≤150 μm.

[0028] In the embodiments of the present application, the initial mixed solution is sand milled to refine the particle size of the oxide electrolyte. When the sand milling is performed to a suitable particle size, i.e., the particle size D50 of the particles in the slurry is between 100 nm and 150 nm, the oxide electrolyte slurry with uniform dispersion is obtained.

[0029] In the embodiments of the present application, the particle size of the particles in the sulfide electrolyte slurry is between 0.8 μm and 1 μm. After the sulfide electrolyte slurry is dried, the particle size of the sulfide composite electrolyte obtained is also between 0.8 μm and 1 μm.

[0030] The embodiments of the present application can effectively avoid the agglomeration problem of the oxide electrolyte ultrafine nano slurry after drying into powder by using the oxide electrolyte coarse powder as one of the raw materials for preparation. The particle size of the electrolyte particles can be refined by sand milling, so that the sulfide composite electrolyte obtained finally has a regular particle morphology and a controllable size.

[0031] Further, the solid content of the initial mixed solution is in the range of 1.8%-2.2%; The mixing mass ratio of the sulfide electrolyte coarse powder to the oxide electrolyte coarse powder is 40:1-60:1; The preset temperature is ≤30℃; The sand milling process uses 0.3 mm zirconia balls.

[0032] In the embodiments of the present application, the solid content of the initial mixture can be about 2%, for example, the solid content ranges from 1.8% to 2.2%. The mass ratio of the sulfide electrolyte powder to the oxide electrolyte powder is 40:1 to 60:1, specifically, it can be 40:1, 45:1, 50:1, 60:1 and other mass ratios within the above range. In an exemplary embodiment, if the mass of the oxide electrolyte powder is 1 g, the mass of the sulfide electrolyte powder can be 40 g, 45 g, 50 g, 56 g, 60 g and other masses between 40 g and 60 g.

[0033] In the embodiments of the present application, when sanding the initial mixture, 0.3 mm zirconium oxide balls are used, and the sanding speed ranges from 1800 rpm to 2200 rpm. Specifically, the sanding speed can be 2000 rpm. In addition, the temperature of sanding needs to be controlled, that is, the aforementioned preset temperature can be less than or equal to 30°C, which maintains the stability of the oxide electrolyte, and a lower temperature is beneficial to obtain a narrower particle size distribution, making the particle morphology of the oxide electrolyte more regular and controllable.

[0034] The embodiments of the present application can effectively refine the electrolyte particles by controlling the addition amount of each raw material and the sanding parameters, so as to customize sulfide composite electrolytes of different sizes.

[0035] Further, as shown in Figure 2 The method comprises: S11: The oxide electrolyte powder and the predetermined solvent are respectively subjected to water removal treatment to obtain water-removed oxide electrolyte powder and water-removed predetermined solvent, and the water-removed oxide electrolyte powder and the water-removed predetermined solvent are transferred to a glove box; the glove box is filled with nitrogen or argon atmosphere; S12: The water-removed oxide electrolyte powder and the water-removed predetermined solvent are mixed in the glove box to obtain the initial mixture.

[0036] In the embodiments of the present application, the oxide electrolyte powder and the predetermined solvent to be used are respectively subjected to water removal treatment, and the water-removed oxide electrolyte powder and the water-removed predetermined solvent are transferred to a glove box. The oxide electrolyte powder and the predetermined solvent are weighed in the glove box and then mixed to obtain an initial mixture, and the solid content of the initial mixture is about 2%.

[0037] In the embodiments of the present application, the glove box is in a nitrogen atmosphere or an argon atmosphere to provide a water-free and oxygen-free preparation environment for subsequent preparation processes, ensure the stability of the preparation process, avoid oxidation or the introduction of impurities, and affect the preparation efficiency and product purity of the sulfide composite electrolyte. In addition, in addition to the glove box, the preparation can also be carried out in a dry room.

[0038] The embodiments of the present application perform water removal treatment on each raw material before preparation, improve the purity and stability of the product, and at the same time improve the preparation efficiency.

[0039] Further, as shown in Figure 3 The initial mixed solution is poured into the sand mill, and sand milling is performed at a preset temperature to obtain an oxide electrolyte slurry, which includes: S21: Pouring the initial mixed solution into the sand mill and sand milling at the preset temperature; S22: Testing the particle size of the initial mixed solution every preset time interval during sand milling, and stopping sand milling when the particle size D50 in the initial mixed solution is between 100 nm and 150 nm, to obtain the oxide electrolyte slurry.

[0040] In the embodiments of the present application, after obtaining the initial mixed solution, it is slowly introduced into the sand mill, sand milling is performed at a preset temperature, and the particle size of the initial mixed solution is tested every preset time interval during sand milling. When the particle size D50 is between 100 nm and 150 nm, sand milling is paused to obtain a uniformly dispersed oxide electrolyte slurry. For particle size testing, a particle size tester can be used. By sand milling the initial mixed solution, the oxide electrolyte can be refined.

[0041] The embodiments of the present application can control the size of oxide particles by sand milling the initial mixed solution to refine the oxide electrolyte.

[0042] Further, as shown in Figure 4 The initial mixed solution is poured into the sand mill, and sand milling is performed at a preset temperature to obtain an oxide electrolyte slurry, which includes: S31: Adding the preset solvent and sulfide electrolyte coarse powder to the oxide electrolyte slurry to obtain a mixed slurry; S32: Continuing sand milling at a first preset rotational speed at the preset temperature to obtain a sand-milled mixed slurry; S33: Adding an additive to the sand-milled mixed slurry and sand milling at a second preset rotational speed to obtain the sulfide electrolyte slurry; the first preset rotational speed is greater than the second preset rotational speed.

[0043] Further, the solid content of the mixed slurry ranges from 18% to 22%; The mass ratio of the additive to the sulfide electrolyte coarse powder is 0.2% to 0.6%; The first preset rotating speed is 1800 rpm to 2200 rpm, and the second preset rotating speed is 800 rpm to 1200 rpm.

[0044] In the embodiment of the present application, after obtaining the oxide electrolyte slurry uniformly dispersed, a preset solvent and a sulfide electrolyte coarse powder are added to obtain a mixed slurry, and the solid content of the sulfide electrolyte coarse powder in the mixed slurry is about 20%, for example, the solid content ranges from 18% to 22%. Continue to sand mill at a first preset rotating speed at a preset temperature, and the sand milling time can be 15 min to 60 min to obtain a sand-milled mixed slurry, and then an additive is added and sand milling is continued at a low speed, i.e., a second preset rotating speed, and the low-speed sand milling time can be 25 min to 35 min to make the mixing more uniform and sufficient, and obtain a sulfide nanoscale electrolyte slurry uniformly coated with oxide nanoparticles. The first preset rotating speed can be 1800 rpm to 2200 rpm, and preferably 2000 rpm, and the second preset rotating speed can be 800 rpm to 1200 rpm, and preferably 1000 rpm.

[0045] In the embodiment of the present application, the additive is used for dispersion and coating adhesion, so that the oxide nanoparticles are uniformly coated on the surface of the sulfide electrolyte to obtain a uniformly dispersed sulfide electrolyte slurry. The mass ratio of the additive to the sulfide electrolyte coarse powder can be 0.2% to 0.6%. If the additive is too little, the gap between part of the oxide and the sulfide electrolyte will not be filled with flexible coating agent, lithium dendrites will be generated, and the ionic conductivity will be reduced. If the additive is too much, the oxide electrolyte nanoparticles cannot be uniformly coated on the surface of the sulfide electrolyte, the electronic conductivity decreases, and too much additive also reduces the ionic conductivity.

[0046] In an exemplary embodiment, the above adding the preset solvent and the sulfide electrolyte coarse powder in the electrolyte slurry and continuing sand milling to obtain a sulfide electrolyte slurry can include: The oxide electrolyte slurry is added with a preset solvent and a sulfide electrolyte coarse powder to obtain a mixed slurry, and the solid content of the sulfide electrolyte coarse powder in the mixed slurry is 18% to 22%; Continue to sand mill at 1800 rpm to 2200 rpm for 15 min to 60 min at a preset temperature to obtain a sand-milled mixed slurry; The additive is added in the mixed slurry after sand milling, and sand milling is performed at 800 rpm-1200 rpm for 25 min-35 min to obtain the sulfide electrolyte slurry; the mass ratio of the additive to the sulfide electrolyte coarse powder is 0.2%-0.6%.

[0047] The embodiment of the present application can make the oxide nanoparticles uniformly coated on the surface of the sulfide electrolyte by controlling the adding sequence and amount of each raw material and the parameters such as the rotation speed of sand milling, so as to obtain the sulfide nanoscale electrolyte slurry.

[0048] Further, the oxide electrolyte coarse powder is one or more of lithium titanium aluminum phosphate, lithium germanium aluminum phosphate, lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, and lithium lanthanum niobium oxide; The preset solvent is one or more of N-methyl pyrrolidone, isobutyl isobutyrate, dimethyl carbonate, ethylene carbonate, diethylene carbonate, and dimethylbenzene; The additive is one or more of hydrogenated styrene-butadiene block copolymer, polyvinylidene fluoride, polyimide, polyacrylonitrile, polyetherimide, and butyl acetate.

[0049] Further, the sulfide electrolyte coarse powder is one or more of LiGePS, LiPSCl, LiPS, LiPSI, and LiPSBr; The drying treatment is one or more of centrifugal drying, vacuum drying, and heating plate solvent evaporation.

[0050] In the embodiment of the present application, the oxide electrolyte coarse powder used can be one or more of lithium titanium aluminum phosphate (LATP), lithium germanium aluminum phosphate (LAGP), lithium lanthanum titanium oxide (LLTO), lithium lanthanum zirconium oxide (LLZO), and lithium lanthanum niobium oxide (LLNO), and is not limited to the above-mentioned substances, but can also be other oxide electrolyte coarse powders. The particle size D100 of the oxide electrolyte coarse powder is ≤150 μm.

[0051] In the embodiment of the present application, the above-mentioned preset solvent, i.e., the refining solvent, needs to use a solvent that does not react with the electrolyte, and can be one or more of N-methyl pyrrolidone (NMP), isobutyl isobutyrate (BIBI), dimethyl carbonate (DMC), ethylene carbonate (EC), diethylene carbonate (DEC), and dimethylbenzene (DMB), and is not limited to the above-mentioned solvents, but can also be other solvents that do not react with the electrolyte.

[0052] In the embodiment of the present application, the above-mentioned additive includes but is not limited to one or more of hydrogenated styrene-butadiene block copolymer (SEBS), polyvinylidene fluoride (PVDF), polyimide (PI), polyacrylonitrile (PAN), polyetherimide (PEI), and butyl acetate (BAC).

[0053] In the embodiment of the present application, the sulfide electrolyte coarse powder includes but is not limited to one or more of LiGePS, LiPSCl, LiPS, LiPSI and LiPSBr, and the corresponding raw material can be selected according to the actual preparation requirement.

[0054] In the embodiment of the present application, after obtaining the sulfide electrolyte slurry, the sulfide electrolyte slurry needs to be dried to remove the solvent to obtain the dried sulfide composite electrolyte. The drying process can be one or more of centrifugal drying, vacuum drying and heating plate solvent evaporation. In an exemplary embodiment, the sulfide electrolyte slurry is vacuum dried to obtain the sulfide composite electrolyte, wherein the temperature of vacuum drying can be 90°C, and the time of vacuum drying can be 12 h. The present application does not limit the drying temperature and the drying time, as long as the solvent is removed.

[0055] The embodiment of the present application can select different raw materials according to the actual preparation requirement, thereby improving the universality of the preparation method. It is easy to mass-produce and popularize.

[0056] The embodiment of the present application also provides a preparation method of a sulfide composite electrolyte, and the specific preparation method includes: The oxide electrolyte coarse powder, the preset solvent and the additive are respectively subjected to water removal treatment, and the water-removed raw materials are transferred to a glove box; The water-removed oxide electrolyte coarse powder and the water-removed preset solvent are mixed in the glove box to obtain an initial mixed solution with a solid content of about 2%; The initial mixed solution is slowly poured into the sand mill, and sand milling is performed at a preset temperature; The particle size of the initial mixed solution in the sand milling process is tested every preset time, and in the case that a suitable particle size (for example, the particle size D50 of the initial mixed solution is between 100 nm and 150 nm) is obtained, the sand milling is stopped, and an oxide electrolyte slurry is obtained; The oxide electrolyte slurry is added with a preset solvent and a sulfide electrolyte coarse powder to obtain a mixed slurry; the solid content of the sulfide electrolyte coarse powder in the mixed slurry is 18%-22%; and the mass ratio of the sulfide electrolyte coarse powder to the oxide electrolyte coarse powder is 40:1-60:1; The sand milling of the mixed slurry is continued at the preset temperature at 1800 rpm-2200 rpm for 15 min-60 min to obtain a sand-milled mixed slurry; The additive is added to the mixed slurry after sanding, and the slurry is sanded for 25 min to 35 min at 800 rpm to 1200 rpm to obtain a sulfide electrolyte slurry; the mass ratio of the additive to the sulfide electrolyte coarse powder is 0.2% to 0.6%; and the particle size in the sulfide electrolyte slurry is between 0.8 μm and 1 μm; The sulfide electrolyte slurry is subjected to drying treatment to obtain a sulfide composite electrolyte.

[0057] The application also provides a sulfide composite electrolyte prepared by the preparation method of the sulfide composite electrolyte. Figure 5 The sulfide composite electrolyte has regular particle morphology, high ionic conductivity, and low electronic conductivity, can ensure the rapid migration of lithium ions in the battery charging and discharging process, realize high-rate charging and discharging of the battery, improve the power performance of the battery, effectively prevent self-discharge of the battery, and improve the energy retention capability and safety of the battery.

[0058] The application also provides a full-solid-state battery comprising the sulfide composite electrolyte.

[0059] The application can avoid the agglomeration problem of the oxide electrolyte ultrafine nano slurry after drying into powder by using the oxide electrolyte coarse powder as one of the preparation raw materials; the oxide electrolyte coarse powder is directly coated on the surface of the sulfide electrolyte by one-pot sanding refinement, which is simple, efficient, and low in cost; by controlling the addition amount of each substance and the sanding parameters, sulfide composite electrolytes of different sizes can be customized, the oxide nanoparticles are uniformly coated on the surface of the sulfide electrolyte, the sulfide composite electrolyte has regular particle morphology, high ionic conductivity, and low electronic conductivity, can ensure the rapid migration of lithium ions in the battery charging and discharging process, realize high-rate charging and discharging of the battery, effectively prevent self-discharge of the battery, and improve the energy retention capability and safety of the battery.

[0060] Embodiment 1: Embodiment 1 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises the following steps. The LATP coarse powder, NMP, and SEBS are dried and dehydrated, and then transferred to a glove box for standby; 6.1 g of the LATP coarse powder is weighed, mixed with 300 g of the NMP solution by stirring with a glass rod to obtain a mixed solution, and then slowly poured into a sanding machine, and the temperature is controlled to be lower than 30℃, the sanding speed is 2000 rpm, and the sanding is performed for 2 h, so that the particle size D50 of the oxide electrolyte slurry is about 150 nm, and a uniformly dispersed oxide electrolyte slurry is obtained. Then, 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder were added, and the operation was continued at a sanding speed of 2000 rpm for 15 min, and then 0.9 g of SEBS additive was added, and low-speed sanding was performed at a sanding speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry was subjected to drying treatment to obtain a sulfide composite electrolyte.

[0061] Example 2: Example 2 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises the following steps: The LLTO coarse powder, NMP, and SEBS were dried to remove water, and then transferred to a glove box for standby; 6.1 g of LLTO coarse powder was weighed, mixed with 300 g of NMP solution using a glass rod, and then slowly poured into a sanding machine, with the temperature controlled below 30°C, the sanding speed being 2000 rpm, and sanding for 2 h, after which the particle size D50 was tested to be about 150 nm, to obtain a uniformly dispersed oxide electrolyte slurry; Then, 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder were added, and the operation was continued at a sanding speed of 2000 rpm for 15 min, and then 0.9 g of SEBS additive was added, and low-speed sanding was performed at a sanding speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry was subjected to drying treatment to obtain a sulfide composite electrolyte.

[0062] Example 3: Example 3 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises the following steps: The LLZO coarse powder, NMP, and SEBS were dried to remove water, and then transferred to a glove box for standby; 6.1 g of LLTO coarse powder was weighed, mixed with 300 g of NMP solution using a glass rod, and then slowly poured into a sanding machine, with the temperature controlled below 30°C, the sanding speed being 2000 rpm, and sanding for 2 h, after which the particle size D50 was tested to be about 150 nm, to obtain a uniformly dispersed oxide electrolyte slurry; Then, 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder were added, and the operation was continued at a sanding speed of 2000 rpm for 15 min, and then 0.9 g of SEBS additive was added, and low-speed sanding was performed at a sanding speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0063] Example 4: Example 4 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LLNO coarse powder, NMP and SEBS are dried to remove water, and then transferred to a glove box for standby; 6.1 g of LLNO coarse powder is weighed, mixed with 300 g of NMP solution using a glass rod, and then slowly poured into a sand mill, with the temperature controlled below 30°C, the sand mill speed at 2000 rpm, and the sand milling time of 2 h. The particle size D50 is about 150 nm, and a uniformly dispersed oxide electrolyte slurry is obtained; Then, 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder are added, and the sand mill speed is continued at 2000 rpm for 15 min. Then, 0.9 g of SEBS additive is added, and the sand mill speed is lowered to 1000 rpm for 15 min. A sulfide electrolyte slurry is obtained. The sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0064] Example 5: Example 5 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP and SEBS are dried to remove water, and then transferred to a glove box for standby; 6.1 g of LATP coarse powder is weighed, mixed with 300 g of NMP solution using a glass rod, and then slowly poured into a sand mill, with the temperature controlled below 30°C, the sand mill speed at 2000 rpm, and the sand milling time of 2 h. The particle size D50 is about 150 nm, and a uniformly dispersed oxide electrolyte slurry is obtained; Then, 917 g of NMP and 306 g of LiGePS (LGPS) sulfide electrolyte coarse powder are added, and the sand mill speed is continued at 2000 rpm for 15 min. Then, 0.9 g of SEBS additive is added, and the sand mill speed is lowered to 1000 rpm for 15 min. A sulfide electrolyte slurry is obtained. The sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0065] Example 6: Example 6 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP and SEBS are dried to remove water, and then transferred to a glove box for standby; Weigh 6.1 g of LATP coarse powder, mix with 300 g of NMP solution with a glass rod, then slowly pour it into the sand mill, control the temperature below 30°C, sand mill speed 2000 rpm, sand mill for 2 h, test the particle size D50 at about 150 nm, get uniformly dispersed oxide electrolyte slurry; Then add 917 g of NMP and 306 g of LiPS (LPS) sulfide electrolyte coarse powder, continue to run at a sand mill speed of 2000 rpm for 15 min, then add 0.9 g of SEBS additive, sand mill at a speed of 1000 rpm for 15 min, get sulfide electrolyte slurry; Dry the above sulfide electrolyte slurry to get sulfide composite electrolyte.

[0066] Example 7: Example 7 provides a sulfide composite electrolyte and a preparation method thereof, the specific preparation method comprising: Dry the LATP coarse powder, NMP, and SEBS, then transfer them to the glove box for standby; Weigh 6.1 g of LATP coarse powder, mix with 300 g of NMP solution with a glass rod, then slowly pour it into the sand mill, control the temperature below 30°C, sand mill speed 2000 rpm, sand mill for 2 h, test the particle size D50 at about 150 nm, get uniformly dispersed oxide electrolyte slurry; Then add 917 g of NMP and 306 g of LiPSI (LPSI) sulfide electrolyte coarse powder, continue to run at a sand mill speed of 2000 rpm for 15 min, then add 0.9 g of SEBS additive, sand mill at a speed of 1000 rpm for 15 min, get sulfide electrolyte slurry; Dry the above sulfide electrolyte slurry to get sulfide composite electrolyte.

[0067] Example 8: Example 8 provides a sulfide composite electrolyte and a preparation method thereof, the specific preparation method comprising: Dry the LATP coarse powder, BIBI, and SEBS, then transfer them to the glove box for standby; Weigh 6.1 g of LATP coarse powder, mix with 300 g of NMP solution with a glass rod, then slowly pour it into the sand mill, control the temperature below 30°C, sand mill speed 2000 rpm, sand mill for 2 h, test the particle size D50 at about 150 nm, get uniformly dispersed oxide electrolyte slurry; Then 917 g of DMB and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder are added, and the operation is continued at a sanding speed of 2000 rpm for 15 min, and then 0.9 g of SEBS additive is added, and low-speed sanding is performed at a sanding speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry is subjected to drying treatment to obtain a sulfide composite electrolyte.

[0068] Example 9: Example 9 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, DMB, and SEBS are dried to remove water, and then transferred to a glove box for standby; 6.1 g of LATP coarse powder is weighed, mixed with 300 g of DMB solution using a glass rod to form a mixed solution, and then slowly poured into a sanding machine, with the temperature controlled below 30°C, and sanding at a speed of 2000 rpm for 2 h, and then the particle size D50 is tested to be about 150 nm, to obtain a uniformly dispersed oxide electrolyte slurry; Then 917 g of DMB and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder are added, and the operation is continued at a sanding speed of 2000 rpm for 15 min, and then 0.9 g of SEBS additive is added, and low-speed sanding is performed at a sanding speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry is subjected to drying treatment to obtain a sulfide composite electrolyte.

[0069] Example 10: Example 10 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, EC, and SEBS are dried to remove water, and then transferred to a glove box for standby; 6.1 g of LATP coarse powder is weighed, mixed with 300 g of EC solution using a glass rod to form a mixed solution, and then slowly poured into a sanding machine, with the temperature controlled below 30°C, and sanding at a speed of 2000 rpm for 2 h, and then the particle size D50 is tested to be about 150 nm, to obtain a uniformly dispersed oxide electrolyte slurry; Then 917 g of DMB and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder are added, and the operation is continued at a sanding speed of 2000 rpm for 15 min, and then 0.9 g of SEBS additive is added, and low-speed sanding is performed at a sanding speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0070] Example 11: Example 11 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP and PVDF are dried to remove water, and then transferred to a glove box for standby; 6.1 g of the LATP coarse powder is weighed, mixed with 300 g of the NMP solution by stirring with a glass rod to form a mixed solution, and then slowly poured into a sand mill, with the temperature controlled below 30°C, and the sand milling speed controlled at 2000 rpm; after sand milling for 2 h, the particle size D50 is tested to be about 150 nm, to obtain a uniformly dispersed oxide electrolyte slurry; Then, 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder are added, and the sand milling speed is continued at 2000 rpm for 15 min; then, 0.9 g of a PVDF additive is added, and the sand milling speed is lowered to 1000 rpm for low-speed sand milling for 15 min, to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0071] Example 12: Example 12 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP and PI are dried to remove water, and then transferred to a glove box for standby; 6.1 g of the LATP coarse powder is weighed, mixed with 300 g of the NMP solution by stirring with a glass rod to form a mixed solution, and then slowly poured into a sand mill, with the temperature controlled below 30°C, and the sand milling speed controlled at 2000 rpm; after sand milling for 2 h, the particle size D50 is tested to be about 150 nm, to obtain a uniformly dispersed oxide electrolyte slurry; Then, 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder are added, and the sand milling speed is continued at 2000 rpm for 15 min; then, 0.9 g of a PVDF additive is added, and the sand milling speed is lowered to 1000 rpm for low-speed sand milling for 15 min, to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0072] Example 13: Example 13 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP and BAC are dried to remove water, and then transferred to a glove box for standby; Weigh 6.1 g of LATP coarse powder, mix with 300 g of NMP solution with a glass rod, then slowly pour it into the sand mill, control the temperature below 30°C, sand mill speed 2000 rpm, sand mill for 2 h, test the particle size D50 at about 150 nm, get uniformly dispersed oxide electrolyte slurry; Then add 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder, continue to run at a sand mill speed of 2000 rpm for 15 min, then add 0.9 g of BAC additive, sand mill at a speed of 1000 rpm for 15 min, get sulfide electrolyte slurry; The above sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0073] Example 14: Example 14 provides a sulfide composite electrolyte and a preparation method thereof, the specific preparation method comprising: Dry the LATP coarse powder, NMP, and SEBS to remove water, then transfer them to a glove box for standby; Weigh 6.1 g of LATP coarse powder, mix with 300 g of NMP solution with a glass rod, then slowly pour it into the sand mill, control the temperature below 30°C, sand mill speed 2000 rpm, sand mill for 2 h, test the particle size D50 at about 150 nm, get uniformly dispersed oxide electrolyte slurry; Then add 917 g of NMP and 306 g of LiPSCl (LPSC) sulfide electrolyte coarse powder, continue to run at a sand mill speed of 2000 rpm for 15 min, then add 0.9 g of BAC additive, sand mill at a speed of 1000 rpm for 15 min, get sulfide electrolyte slurry; The above sulfide electrolyte slurry is dried to obtain a sulfide composite electrolyte.

[0074] Example 15: Example 15 provides a sulfide composite electrolyte and a preparation method thereof, the specific preparation method comprising: Dry the LATP coarse powder, NMP, and SEBS to remove water, then transfer them to a glove box for standby; Weigh 6.1 g of LATP coarse powder, mix with 300 g of NMP solution with a glass rod, then slowly pour it into the sand mill, control the temperature below 30°C, sand mill speed 2000 rpm, sand mill for 2 h, test the particle size D50 at about 150 nm, get uniformly dispersed oxide electrolyte slurry; Then 917 g NMP and 306 g LiPSCl (LPSC) sulfide electrolyte coarse powder were added, and the sanding speed was continued at 2000 rpm for 15 min, 1.8 g SEBS additive was added, and the sanding speed was low at 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry was dried to obtain a sulfide composite electrolyte. The parameter comparison table of Examples 14 and 15 is shown in Table 1.

[0075] Table 1. Parameter comparison table of Examples 14 and 15

[0076] Example 16: Example 16 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP, and SEBS were dried to remove water, and then transferred to a glove box for standby; 6.1 g of LATP coarse powder was weighed, mixed with 300 g of NMP solution using a glass rod, and then slowly poured into a sand mill, with the temperature controlled below 30°C, the sanding speed was 2000 rpm, and the sanding time was 2 h. After testing, the particle size D50 was about 150 nm, and a uniformly dispersed oxide electrolyte slurry was obtained; Then 917 g NMP and 306 g LiPSCl (LPSC) sulfide electrolyte coarse powder were added, and the sanding speed was continued at 2000 rpm for 15 min, 1.8 g SEBS additive was added, and the sanding speed was low at 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry was dried to obtain a sulfide composite electrolyte.

[0077] Example 17: Example 17 provides a sulfide composite electrolyte and a preparation method thereof, and the specific preparation method comprises: The LATP coarse powder, NMP, and SEBS were dried to remove water, and then transferred to a glove box for standby; 6.1 g of LATP coarse powder was weighed, mixed with 300 g of NMP solution using a glass rod, and then slowly poured into a sand mill, with the temperature controlled below 30°C, the sanding speed was 2000 rpm, and the sanding time was 2 h. After testing, the particle size D50 was about 150 nm, and a uniformly dispersed oxide electrolyte slurry was obtained; Then 917 g NMP and 366 g LiPSCl (LPSC) sulfide electrolyte coarse powder were added, and the sanding was continued at a speed of 2000 rpm for 15 min, and then 0.9 g SEBS additive was added, and the sanding was continued at a speed of 1000 rpm for 15 min to obtain a sulfide electrolyte slurry; The sulfide electrolyte slurry was dried to obtain a sulfide composite electrolyte. The parameter comparison table of Example 16 and Example 17 is shown in Table 2.

[0078] Table 2. Parameter comparison table of Example 16 and Example 17

[0079] In the examples of the present application, the difference between Example 2-4 and Example 1 is that the oxide electrolyte used in Example 2 is LLTO, the oxide electrolyte used in Example 3 is LLZO, and the oxide electrolyte used in Example 4 is LLNO; the difference between Example 5-7 and Example 1 is that the sulfide electrolyte used in Example 5 is LiGePS (LGPS), the sulfide electrolyte used in Example 6 is LiPS (LPS), and the sulfide electrolyte used in Example 7 is LiPSI (LPSI); the difference between Example 8-10 and Example 1 is that the thinning solvent used in Example 8 is BIBI, the thinning solvent used in Example 9 is DMB, and the thinning solvent used in Example 10 is EC; the difference between Example 11-13 and Example 1 is that the additive used in Example 11 is PVDF, the additive used in Example 12 is PI, and the additive used in Example 13 is BAC; the difference between Example 14, Example 15 and Example 1 is that the mass ratio of additive to sulfide electrolyte coarse powder in Example 14 is 0.2%:1, and the mass ratio of additive to sulfide electrolyte coarse powder in Example 14 is 0.6%:1; the difference between Example 16, Example 17 and Example 1 is that the mass ratio of sulfide electrolyte coarse powder to oxide electrolyte coarse powder in Example 16 is 40:1, and the mass ratio of sulfide electrolyte coarse powder to oxide electrolyte coarse powder in Example 17 is 60:1.

[0080] Comparative Example 1: Comparative Example 1 provides a sulfide electrolyte and a preparation method thereof, and the specific preparation method is based on the method provided in Example 1, but no oxide electrolyte coarse powder and additive is added, and finally a sulfide electrolyte is prepared.

[0081] Comparative Example 2: Comparative Example 2 provides a sulfide composite electrolyte and its preparation method. The specific preparation method is based on the method provided in Example 1, but without the addition of additives, and finally a sulfide composite electrolyte is prepared.

[0082] Comparative Example 3: Comparative Example 3 provides a sulfide electrolyte and its preparation method. The specific preparation method is based on the method provided in Example 1, but without adding oxide electrolyte powder, and finally a sulfide electrolyte is prepared.

[0083] Comparative Example 4: Comparative Example 4 provides a sulfide composite electrolyte and its preparation method. The specific preparation method is based on the method provided in Example 1, but the mass ratio of the additive to the crude sulfide electrolyte powder is adjusted to 0.1%:1, and a sulfide composite electrolyte is finally prepared.

[0084] Comparative Example 5: Comparative Example 5 provides a sulfide composite electrolyte and its preparation method. The specific preparation method is based on the method provided in Example 1, but the mass ratio of additives to crude sulfide electrolyte powder is adjusted to 0.7%:1, ultimately yielding a sulfide composite electrolyte. The parameter comparison table between Comparative Example 4 and Comparative Example 5 is shown in Table 3 below.

[0085] Table 3. Parameter Comparison Table between Comparative Example 4 and Comparative Example 5

[0086] Comparative Example 6: Comparative Example 6 provides a sulfide composite electrolyte and its preparation method. The specific preparation method is based on the method provided in Example 1, but the mass ratio of sulfide electrolyte coarse powder to oxide electrolyte coarse powder is adjusted to make the mass ratio of sulfide electrolyte coarse powder to oxide electrolyte coarse powder 30:1, and finally a sulfide composite electrolyte is prepared.

[0087] Comparative Example 7: Comparative Example 6 provides a sulfide composite electrolyte and its preparation method. The specific preparation method is based on the method provided in Example 1, but the mass ratio of sulfide electrolyte coarse powder to oxide electrolyte coarse powder is adjusted to 70:1, ultimately yielding a sulfide composite electrolyte. The parameter comparison table between Comparative Example 6 and Comparative Example 7 is shown in Table 4 below.

[0088] Table 4. Parameter Comparison Table between Comparative Example 6 and Comparative Example 7

[0089] In the embodiments of the present application, the electrolytes obtained in the above embodiments and comparative examples were also subjected to performance tests. The electrolytes obtained in the above embodiments and comparative examples were respectively placed in a full solid-state battery mold, kept under a pressure of 200 Mbar for 3 min, and matched with blocking electrodes at both ends, and the ion conductivity and electronic conductivity were tested by an alternating current impedance method, while the ion conductivity retention rate and the electronic conductivity reduction rate of each embodiment and comparative example were compared with those of comparative example 1 as the standard, and the final test results are shown in Table 5.

[0090] Table 5. Test result summary table of each embodiment and comparative example

[0091] In the embodiments of the present application, it can be seen from the above test results that, compared with the pure sulfide electrolyte in Comparative Example 1, the ion conductivity retention rates of the improved oxide particle coated sulfide composite electrolyte are all above 80%, and the electronic conductivity reduction rates are all above 95%. It can be known from the test results of Example 1 to Example 4 that, the sulfide electrolyte coated with different types of oxide electrolyte can achieve a high ion conductivity retention rate (above 90%) and a high electronic conductivity reduction rate (above 98%). It can be known from the test results of Example 5 to Example 7 that, according to the preparation method of the sulfide electrolyte provided in the embodiments of the present application, different types of sulfide electrolyte are coated, and the finally prepared sulfide composite electrolyte can achieve a high ion conductivity retention rate (above 85%) and a high electronic conductivity reduction rate (above 98%). It can be known from the test results of Example 8 to Example 10 that, different refining solvents are used in the preparation process, and the finally prepared sulfide composite electrolyte can achieve a high ion conductivity retention rate (above 84%) and a high electronic conductivity reduction rate (above 98%). It can be known from the test results of Example 11 to Example 13 that, different additives are added in the preparation process, and the finally prepared sulfide composite electrolyte can achieve a high ion conductivity retention rate (above 85%) and a high electronic conductivity reduction rate (above 98%). It can be known from the test results of Example 14 and Example 15 that, under the condition that the mass ratio of the additive to the sulfide electrolyte coarse powder is 0.2%-6%, the finally prepared sulfide composite electrolyte can achieve a high ion conductivity retention rate (above 81%) and a high electronic conductivity reduction rate (above 95%). It can be known from the test results of Example 16 and Example 17 that, under the condition that the mass ratio of the sulfide electrolyte coarse powder to the oxide electrolyte coarse powder is (40-60): 1, the finally prepared sulfide composite electrolyte can achieve a high ion conductivity retention rate (above 82%) and a high electronic conductivity reduction rate (above 95%).

[0092] In the embodiments of the present application, from the test results of Comparative Example 2, it can be obtained that, if the sulfide electrolyte is directly mixed with the oxide particles without adding the additive, although the oxide particles have high dielectric constant, since the two electrolytes are rigid materials, the solid-solid interface gap precipitation is easy to form lithium dendrites, consume active lithium ions, reduce the effective carrier concentration, and cause the ion conductivity to be greatly reduced. From the test results of Comparative Example 3, it can be obtained that, if the oxide electrolyte is not added and only the additive for dispersion and coating is added, the ion conductivity of such additive itself is relatively low, which leads to the reduction of the ion conductivity of the overall composite material. From the test results of Comparative Example 4 and Comparative Example 5, it can be obtained that, if the additive is too little, the gap between part of the oxide and the sulfide electrolyte is not filled with flexible coating agent, lithium dendrites are generated, and the ion conductivity is reduced; if the additive is too much, the oxide electrolyte nanoparticles cannot be uniformly coated on the surface of the sulfide electrolyte, the electronic conductivity reduction rate is low, and too much additive also leads to the reduction of the ion conductivity. From the test results of Comparative Example 6 and Comparative Example 7, it can be obtained that, if the sulfide electrolyte is more and the oxide electrolyte is less, although the ion conductivity retention rate is high, the electronic conductivity reduction rate is low; if the oxide electrolyte is more and the sulfide electrolyte is less, the overall ion conductivity is low.

[0093] Therefore, according to the preparation method provided in the embodiments of the present application, and by controlling the mass ratio of the sulfide electrolyte and the oxide electrolyte and the mass ratio between the additive and the sulfide electrolyte, the electronic conductivity can be greatly reduced under the condition of extremely low reduction of the ion conductivity, the conduction characteristics of ions and electrons are ingeniously balanced, the sulfide composite electrolyte finally prepared has high ion conductivity, can ensure the rapid migration of lithium ions in the battery charging and discharging process, realizes the high-rate charging and discharging of the battery, and improves the power performance of the battery; and has low electronic conductivity, can effectively prevent the self-discharge of the battery, and improves the energy retention capability and safety of the battery.

[0094] As can be seen from the above embodiments provided by the present application, the present application mixes the oxide electrolyte coarse powder with the preset solvent to obtain an initial mixed solution; pours the initial mixed solution into a sand mill, and performs sand milling treatment at a preset temperature to obtain an oxide electrolyte slurry; adds the preset solvent and the sulfide electrolyte coarse powder into the electrolyte slurry, and continues to perform sand milling treatment to obtain a sulfide electrolyte slurry; and performs drying treatment on the sulfide electrolyte slurry to obtain a sulfide composite electrolyte. By using the oxide electrolyte coarse powder as one of the preparation raw materials, the present application can avoid the problem of agglomeration of the oxide electrolyte superfine nano slurry after being dried into powder; by the one-pot sand milling refinement method, the oxide electrolyte coarse powder is refined into nanoparticles in one pot and directly coated on the surface of the sulfide electrolyte, the preparation method is simple and efficient, and the cost is relatively low; by controlling the addition amount of each substance and the sand milling parameters, sulfide composite electrolytes with different sizes can be customized, the oxide nanoparticles are uniformly coated on the surface of the sulfide electrolyte, the sulfide composite electrolyte has a regular particle morphology, has high ionic conductivity and low electronic conductivity, can ensure the rapid migration of lithium ions in the battery charging and discharging process, realize high-rate charging and discharging of the battery, and can effectively prevent self-discharge of the battery, improve the energy retention capability and safety of the battery.

[0095] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a sulfide composite electrolyte, characterized by, The method comprises: Mixing oxide electrolyte coarse powder with a preset solvent to obtain an initial mixed solution; Pouring the initial mixed solution into a sand mill and performing sand milling treatment at a preset temperature to obtain an oxide electrolyte slurry; Adding the preset solvent and sulfide electrolyte coarse powder to the electrolyte slurry and continuing to perform sand milling treatment to obtain a sulfide electrolyte slurry; Performing drying treatment on the sulfide electrolyte slurry to obtain the sulfide composite electrolyte.

2. The method of claim 1, wherein, The particle size D100 of the oxide electrolyte coarse powder is ≤150 μm; The particle size D50 of the oxide electrolyte slurry is between 100 nm and 150 nm; The particle size of the sulfide electrolyte slurry is between 0.8 μm and 1 μm.

3. The method of claim 2, wherein, The solid content of the initial mixed solution ranges from 1.8% to 2.2%; The mass ratio of the sulfide electrolyte coarse powder to the oxide electrolyte coarse powder is 40:1 to 60:1; The preset temperature is ≤30℃; The sand milling treatment uses 0.3 mm zirconium oxide balls.

4. The method of claim 1, wherein, The step of adding the preset solvent and sulfide electrolyte coarse powder to the electrolyte slurry and continuing to perform sand milling treatment to obtain a sulfide electrolyte slurry comprises: Adding the preset solvent and sulfide electrolyte coarse powder to the oxide electrolyte slurry to obtain a mixed slurry; Continuing to perform sand milling at a first preset rotating speed under the preset temperature to obtain a sand-milled mixed slurry; Adding an additive to the sand-milled mixed slurry and performing sand milling at a second preset rotating speed to obtain the sulfide electrolyte slurry; the first preset rotating speed is greater than the second preset rotating speed.

5. The method of claim 4, wherein, The solid content of the mixed slurry ranges from 18% to 22%; The mass ratio of the additive to the sulfide electrolyte coarse powder is 0.2% to 0.6%; The first preset rotating speed is 1800 rpm to 2200 rpm, and the second preset rotating speed is 800 rpm to 1200 rpm.

6. The method of claim 1, wherein, The step of pouring the initial mixed solution into a sand mill and performing sand milling treatment at a preset temperature to obtain an oxide electrolyte slurry comprises: Pouring the initial mixed solution into the sand mill and performing sand milling at the preset temperature; Testing the particle size of the initial mixed solution every preset time interval during the sand milling process, and stopping the sand milling when the particle size D50 of the initial mixed solution is between 100 nm and 150 nm, to obtain the oxide electrolyte slurry.

7. The method of claim 4, wherein, The step of mixing oxide electrolyte coarse powder with a preset solvent to obtain an initial mixed solution comprises: Performing water removal treatment on the oxide electrolyte coarse powder and the preset solvent respectively to obtain water-removed oxide electrolyte coarse powder and water-removed preset solvent, and transferring the water-removed oxide electrolyte coarse powder and the water-removed preset solvent to a glove box; the glove box is filled with a nitrogen atmosphere or an argon atmosphere; Mixing the water-removed oxide electrolyte coarse powder and the water-removed preset solvent in the glove box to obtain the initial mixed solution.

8. The method of claim 7, wherein, The oxide electrolyte coarse powder is one or more of lithium aluminum titanium phosphate, lithium aluminum germanium phosphate, lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, and lithium lanthanum niobium oxide; The pre-set solvent is one or more of N-methyl pyrrolidone, isobutyl isobutyrate, dimethyl carbonate, ethylene carbonate, diethylene carbonate, and dimethylbenzene; The additive is one or more of hydrogenated styrene-butadiene block copolymer, polyvinylidene fluoride, polyimide, polyacrylonitrile, polyetherimide, and butyl acetate.

9. The method of claim 1, wherein, The sulfide electrolyte coarse powder is one or more of LiGePS, LiPSCl, LiPS, LiPSI, and LiPSBr; The drying treatment is one or more of centrifugal drying, vacuum drying, and heating plate solvent evaporation.

10. A sulfide composite electrolyte, characterized by, The sulfide composite electrolyte is prepared by the preparation method of the sulfide composite electrolyte according to any one of claims 1-9.

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