Liquid phase ultrasonic preparation method for solid electrolyte and obtained solid electrolyte

Abstract

The present invention relates to the field of solid electrolyte technology, and in particular, to a liquid-phase ultrasonic preparation method for a solid electrolyte and the resulting solid electrolyte. The liquid-phase ultrasonic preparation method for a solid electrolyte of the present invention comprises the following steps: mixing a halide metal salt, a halide lithium salt and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system; performing rotary evaporation treatment on the first mixed system, collecting the solid matter after rotary evaporation and calcining it. The present invention uses a non-polar solvent to crush and nano-size the raw materials under high-energy ultrasonic conditions to form a suspension-like liquid, so as to expand the microscopic contact surface of the precursor powder material, thereby improving the purity and conductivity of the obtained solid electrolyte.

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolytes, and in particular to a liquid-phase ultrasonic preparation method for a solid electrolyte and the obtained solid electrolyte. Background Art

[0002] Solid-state batteries use non-flammable solid-state battery electrolytes to replace flammable organic liquid electrolytes, which can greatly improve the safety of the battery system. At the same time, they can better adapt to high-energy positive and negative electrodes and reduce the weight of the system, achieving a simultaneous increase in energy density.

[0003] Solid electrolyte materials are the core materials of solid-state battery components. Commonly used materials are sulfides, oxides, polymers, and halides. Among them, the Coulomb force of monovalent anions in the halide crystal skeleton on lithium ions is lower than that of sulfides and oxides. In addition, the anion radius is lower than that of sulfides and oxides, which makes halides more mechanically deformable. Halide solid electrolytes can be well matched with high-voltage positive electrodes (>4V) without the need for additional protective layers. The most important thing is that halogen anions do not react with oxygen, which completely eliminates the possibility of fire and combustion at the elemental level. A series of advantages make halide solid electrolytes one of the alternative options for excellent solid-state battery electrolyte materials, but the current preparation is mainly limited to the glove box, and mass production cannot be achieved, which hinders the pace of mass production of solid-state batteries.

[0004] There are several traditional preparation processes for halide solid electrolytes: 1. Dry high-energy ball milling: Generally, halide precursor powder materials of a certain stoichiometric ratio are put into a ball mill. During the high-speed rotation process, the collision, extrusion, shearing and other operations between the grinding balls cause the chemical bonds of the materials to break and recombine to form new target substances. 2. Solvent method: Generally, a halide solid electrolyte precursor of a certain stoichiometric ratio is fully dissolved in a polar solvent, and then the solvent is removed by high temperature, so that the precursor powder material undergoes crystal rearrangement during the dissolution and solution process to form a new phase. This is an effective method for the mass synthesis of halide solid electrolytes. 3. Melting method: Generally, halide solid electrolyte materials of a certain stoichiometric ratio are dry-ground and mixed, and the mixture reaches a molten state at the melting point temperature to synthesize a new phase.

[0005] The main improvements to the three processes mentioned above are: 1. Dry high-energy ball milling. This method limits the batch size of the material to the volume of the milling jar. Large-scale milling jars are required for large-scale preparation. Furthermore, this method is time-consuming and energy-intensive. Typically, a batch of halide solid electrolyte materials requires continuous milling for 24-48 hours, or even longer, resulting in significant time and cost. Dry ball milling consumes significant energy, and the milling equipment must operate continuously during the milling process. Energy consumption assessments show that a single high-power planetary ball mill accounts for over 75% of the laboratory's total energy consumption per day. Dry ball milling is a complex process, and materials tend to agglomerate and adhere to the milling wall during milling. A glove box is required, and repeated removal and scraping of adhered material is necessary for continued milling. This process introduces moisture and other impurities, degrading material performance. The solvent method is an optional process for mass production of solid electrolyte materials, but this method has obvious defects: when the halide solid precursor is dissolved in a polar organic solvent, the metal ions will form complexes with the organic functional groups. The high-temperature solvent removal process makes it difficult to separate the complexes. The organic matter remaining in the subsequent calcination will carbonize at high temperatures, affecting the purity of the material and reducing the electrical conductivity of the material. In addition, halides are highly sensitive to moisture and will combine with trace water that has not been completely removed from the solvent to form oxides during the subsequent high-temperature calcination process, greatly reducing the electrical conductivity of the halide solid electrolyte. Finally, the melting method requires a large amount of energy, and the high energy cost in mass production makes this method unsustainable.

[0006] Therefore, in order to solve the problem of batch synthesis of halide solid electrolyte materials, the solvent method is still the most advantageous solution. What needs to be solved at present is: the complexation problem of the precursor powder material with the organic functional group after dissolution, and the resulting solid electrolyte has low purity and low conductivity.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] One object of the present invention is to provide a liquid-phase ultrasonic preparation method for solid electrolytes to solve the technical problems of low purity and low conductivity in the prior art when solid electrolytes are prepared by dissolution method.

[0009] Another object of the present invention is to provide a solid electrolyte prepared by a liquid phase ultrasonic preparation method of a solid electrolyte.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0011] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0012] A halide metal salt, a halide lithium salt and a non-polar solvent are mixed and ultrasonically treated to obtain a first mixed system; the first mixed system is subjected to rotary evaporation, and the solids after rotary evaporation are collected and calcined.

[0013] In one embodiment, the ultrasonic treatment time is 0.1 to 48 hours, and the ultrasonic treatment power is 10 to 1000W.

[0014] In one embodiment, the temperature of the ultrasonic treatment is 25-60°C.

[0015] In one embodiment, the ultrasonic treatment time is 0.5 to 10 h; the ultrasonic treatment power is 400 to 800 W; and the ultrasonic treatment temperature is 25 to 50° C.

[0016] In one embodiment, the non-polar solvent includes at least one of benzene, carbon tetrachloride, isooctane, toluene, dichloromethane, n-hexane, cyclohexane, heptane and liquid paraffin.

[0017] In one embodiment, the halide metal salt includes at least one of indium chloride, indium bromide, indium iodide, indium fluoride, yttrium chloride, yttrium bromide, yttrium iodide, yttrium fluoride, scandium chloride, scandium bromide, scandium iodide, scandium fluoride, scandium chloride, scandium bromide, scandium iodide, scandium fluoride, and MX3; wherein M is selected from Tb, Dy, Ho, Er, Tm, Yb or Lu, and X is selected from Cl, Br, I or F;

[0018] In one embodiment, the halide lithium salt includes at least one of lithium chloride, lithium bromide, lithium iodide, and lithium fluoride.

[0019] In one embodiment, the molar ratio of the lithium halide salt to the metal halide salt is (2.5-3.5): (0.8-1.2).

[0020] In one embodiment, the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is (1-100) g: (5-200) mL.

[0021] In one embodiment, the vacuum pressure of the rotary evaporation is 0.08 to 0.12 MPa; the temperature of the rotary evaporation is 110 to 130° C.; and the rotation speed of the rotary evaporation is 50 to 70 r / min.

[0022] In one embodiment, the solids after rotary evaporation are collected, ground to a particle size D50 < 100 μm, and then calcined.

[0023] In one embodiment, the calcination temperature is 60 to 500° C., and the calcination time is 1 to 12 hours.

[0024] The solid electrolyte prepared by the liquid phase ultrasonic preparation method of the solid electrolyte as described above has an electrical conductivity of 0.9 to 1.5 mS / cm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention adopts a non-polar solvent and, under ultrasonic treatment conditions, conducts ultrasonic waves in the liquid phase to break up the raw materials and then nano-crush them into a suspension-like liquid, thereby expanding the microscopic contact surface of the precursor powder material. Compared with the traditional solvent method, the method of the present invention has stronger protection for the characteristics of the material itself. The non-polar solvent will not produce side reactions with the metal cations in the material, thereby improving the purity and conductivity of the solid electrolyte. DETAILED DESCRIPTION

[0027] The embodiments of the present invention will be described in detail below with reference to the examples. However, it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all commercially available conventional products.

[0028] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0029] A halide metal salt, a halide lithium salt and a non-polar solvent are mixed and ultrasonically treated to obtain a first mixed system; the first mixed system is subjected to rotary evaporation, and the solids after rotary evaporation are collected and calcined.

[0030] The present invention adopts a non-polar solvent instead of a polar solvent to avoid side reactions between the material and the solvent. The precursor powder material is nanosized under high-energy ultrasonic crushing conditions and fully dispersed in the solvent to form a suspension-like liquid. The solvent is then removed under the closed, high-temperature, dynamic conditions of a rotary evaporator to ensure close adhesion of the materials. Finally, high-temperature calcination is performed to form a high-purity, high-conductivity solid electrolyte material. This method can effectively avoid the complex reaction between the metal salt and the solvent.

[0031] The principle behind using non-polar solvents as dispersants to effectively avoid side reactions is as follows: Non-polar solvents are a class of solvents with low dielectric constants, also known as inert solvents. These solvents neither undergo proton transport reactions nor solvate with solutes. In these solvents, halide precursors undergo only physical dispersion, without breaking or reconstructing chemical bonds. This effectively avoids protonation side reactions between the metal cations and organic functional groups in the material, fundamentally improving the purity of the material. High-energy ultrasound is used to fully disperse and contact the materials. The dramatic change in sound pressure during ultrasonic wave propagation through the liquid causes intense cavitation and emulsification, generating millions of tiny cavitation bubbles per second. These bubbles, rapidly generated and continuously imploding under the influence of the sound pressure, generate powerful impact forces and negative pressure suction, sufficient to break up inorganic metal and lithium salts, nanostructuring them and forming a suspension-like dispersion in the non-polar solvent.

[0032] In one embodiment, the ultrasonic treatment time is 0.1 to 48 hours, for example, 0.1 h, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 15 h, 18 h, 20 h, 25 h, 30 h, 35 h, 38 h, 40 h, 42 h, 45 h, 48 h, etc.

[0033] In one embodiment, the power of the ultrasonic treatment is 10 to 1000 W, for example, 10 W, 100 W, 200 W, 300 W, 400 W, 500 W, 600 W, 700 W, 800 W, 900 W, 1000 W, etc.

[0034] The present invention utilizes appropriate ultrasonic treatment power and duration, thereby facilitating nano-dispersion of the halide metal salt and the halide lithium salt in the non-polar solvent, forming a suspension-like solution. This facilitates subsequent rotary evaporation and calcination, thereby facilitating the production of a high-purity, high-conductivity solid electrolyte. If the ultrasonic treatment duration is too short or the power is too low, the ultrasonic effect is not significant, failing to achieve the desired dispersion effect of the present invention, thereby reducing the purity and conductivity of the solid electrolyte.

[0035] In one embodiment, the temperature of the ultrasonic treatment is room temperature to 60°C. In one embodiment, the ultrasonic temperature is initially room temperature and increases as the ultrasonic time is prolonged. In one embodiment, the temperature of the ultrasonic treatment is 25 to 60°C, for example, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C or 55°C.

[0036] In one embodiment, the ultrasonic treatment time is 0.5 to 10 h; the ultrasonic treatment power is 400 to 8000 W; and the ultrasonic treatment temperature is 25 to 50°C.

[0037] In one embodiment, the non-polar solvent includes at least one of benzene, carbon tetrachloride, isooctane, toluene, dichloromethane, n-hexane, cyclohexane, heptane and liquid paraffin. The non-polar solvent of the present invention can be selected from any one of the above-mentioned non-polar solvents, or a combination of two or more of the above-mentioned non-polar solvents can be selected, such as a combination of benzene and toluene, a combination of dichloromethane, n-hexane and cyclohexane, a combination of isooctane, heptane and liquid paraffin, etc. Different non-polar solvents have slightly different effects on the materials as dispersants. Dichloromethane is a kind of halogenated hydrocarbon, and its main group is chlorine. The same element has the least effect on the formation process of the halide precursor material. Therefore, the solid electrolyte prepared by using it as a dispersant has higher purity and conductivity.

[0038] In one embodiment, the halide metal salt includes at least one of indium chloride, indium bromide, indium iodide, indium fluoride, yttrium chloride, yttrium bromide, yttrium iodide, yttrium fluoride, scandium chloride, scandium bromide, scandium iodide, scandium fluoride, scandium chloride, scandium bromide, scandium iodide, scandium fluoride and MX3; wherein M is selected from Tb, Dy, Ho, Er, Tm, Yb or Lu, and X is selected from Cl, Br, I or F.

[0039] In one embodiment, the halide lithium salt includes at least one of lithium chloride, lithium bromide, lithium iodide, and lithium fluoride.

[0040] In one embodiment, the molar ratio of the lithium halide salt to the metal halide salt is (2.5-3.5):(0.8-1.2), for example, 2.5:0.8, 2.8:1, 3:1, 3.2:1.1, 3.5:1.2, etc.

[0041] In one embodiment, the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is (1-100) g: (5-200) mL, for example, 1 g:5 mL, 5 g:10 mL, 20 g:30 mL, 30 g:mL, 50 g:mL, 50 g:100 mL, 70 g:150 mL, 100 g:200 mL, etc.

[0042] In one embodiment, the vacuum pressure of the rotary evaporation is 0.08 to 0.12 MPa, for example, 0.08 MPa, 0.09 MPa, 0.1 MPa, 0.11 MPa, 0.12 MPa, etc.; the temperature of the rotary evaporation is 110 to 130°C, for example, 110°C, 115°C, 118°C, 120°C, 125°C, 130°C, etc.; the rotation speed of the rotary evaporation is 50 to 70 r / min, for example, 50 r / min, 55 r / min, 60 r / min, 65 r / min, 70 r / min, etc.

[0043] The rotary evaporation of the present invention adopts appropriate vacuum pressure, temperature and rotation speed, which can effectively remove the solvent and make the materials after the solvent is removed closely fit, thereby improving the purity and conductivity of the finally obtained solid electrolyte.

[0044] In one embodiment, the solids after rotary evaporation are collected and ground to a particle size D50 of less than 100 μm before calcining. In one embodiment, the solids after rotary evaporation are collected and ground to a particle size D50 of 10 nm to 99 μm, for example, 50 nm, 100 nm, 150 nm, 200 nm, 500 nm, 1 μm, 10 μm, 20 μm, 50 μm, 90 μm, etc.

[0045] In one embodiment, the calcination temperature is 180-260° C., for example, 180° C., 200° C., 210° C., 220° C., 230° C., 240° C., or 250° C., etc. The calcination time is 1-12 h, for example, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 10 h, etc.

[0046] The present invention adopts appropriate calcination and calcination time to ensure the physical and chemical properties of the solid electrolyte, so that it has high purity and high conductivity.

[0047] According to another aspect of the present invention, the present invention also relates to a solid electrolyte prepared by the liquid phase ultrasonic preparation method of the solid electrolyte as described above; the electrical conductivity of the solid electrolyte is 0.9 to 1.5 mS / cm.

[0048] The following is further explained with reference to specific embodiments and comparative examples.

[0049] Example 1

[0050] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0051] (1) mixing a halide metal salt, a halide lithium salt, and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system (suspension-like solution);

[0052] The halide metal salt is indium chloride, the halide lithium salt is lithium chloride, and the non-polar solvent is ethylene dichloride; the molar ratio of the halide lithium salt to the halide metal salt is 3:1; the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is 2g:10mL; the ultrasonic treatment time is 3h; and the power of the ultrasonic equipment used in the ultrasonic treatment is 600W;

[0053] (2) using a rotary evaporator to rotary evaporate the first mixed system, collecting the solids after rotary evaporation, grinding them, and then transferring them to a tube furnace or a muffle furnace for calcination;

[0054] The vacuum pressure of the rotary evaporation is 0.01 MPa; the oil bath temperature of the rotary evaporation is 80° C.; the rotation speed of the rotary evaporation is 60 r / min; the calcination temperature is 200° C., and the calcination time is 4 h.

[0055] Example 2

[0056] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0057] (1) mixing a halide metal salt, a halide lithium salt, and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system (suspension-like solution);

[0058] The halide metal salt is indium chloride, the halide lithium salt is lithium chloride, and the non-polar solvent is toluene; the molar ratio of the halide lithium salt to the halide metal salt is 3:1; the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is 2g:10mL; the ultrasonic treatment time is 3h; and the power of the ultrasonic equipment used in the ultrasonic treatment is 600W;

[0059] (2) using a rotary evaporator to rotary evaporate the first mixed system, collecting the solids after rotary evaporation, grinding them, and then transferring them to a tube furnace or a muffle furnace for calcination;

[0060] The vacuum pressure of the rotary evaporation is 0.01 MPa; the oil bath temperature of the rotary evaporation is 80° C.; the rotation speed of the rotary evaporation is 60 r / min; the calcination temperature is 200° C., and the calcination time is 4 h.

[0061] Example 3

[0062] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0063] (1) mixing a halide metal salt, a halide lithium salt, and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system (suspension-like solution);

[0064] The halide metal salt is indium chloride, the halide lithium salt is lithium chloride, and the non-polar solvent is n-hexane; the molar ratio of the halide lithium salt to the halide metal salt is 3:1; the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is 2 g:10 mL; the ultrasonic treatment time is 3 h; and the power of the ultrasonic equipment used in the ultrasonic treatment is 600 W.

[0065] (2) using a rotary evaporator to rotary evaporate the first mixed system, collecting the solids after rotary evaporation, grinding them, and then transferring them to a tube furnace or a muffle furnace for calcination;

[0066] The vacuum pressure of the rotary evaporation is 0.01 MPa; the oil bath temperature of the rotary evaporation is 80° C.; the rotation speed of the rotary evaporation is 60 r / min; the calcination temperature is 200° C., and the calcination time is 4 h.

[0067] Example 4

[0068] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0069] (1) mixing a halide metal salt, a halide lithium salt, and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system (suspension-like solution);

[0070] The halide metal salt is indium chloride, the halide lithium salt is lithium chloride, and the non-polar solvent is cyclohexane; the molar ratio of the halide lithium salt to the halide metal salt is 3:1; the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is 2g:10mL; the ultrasonic treatment time is 3h; and the power of the ultrasonic equipment used in the ultrasonic treatment is 600W;

[0071] (2) using a rotary evaporator to rotary evaporate the first mixed system, collecting the solids after rotary evaporation, grinding them, and then transferring them to a tube furnace or a muffle furnace for calcination;

[0072] The vacuum pressure of the rotary evaporation is 0.01 MPa; the oil bath temperature of the rotary evaporation is 80° C.; the rotation speed of the rotary evaporation is 60 r / min; the calcination temperature is 200° C., and the calcination time is 4 h.

[0073] Example 5

[0074] The liquid phase ultrasonic preparation method of the solid electrolyte comprises the following steps:

[0075] (1) mixing a halide metal salt, a halide lithium salt, and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system (suspension-like solution);

[0076] The halide metal salt is indium chloride, the halide lithium salt is lithium chloride, and the non-polar solvent is isooctane; the molar ratio of the halide lithium salt to the halide metal salt is 3:1; the volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is 2g:10mL; the ultrasonic treatment time is 3h; and the power of the ultrasonic equipment used in the ultrasonic treatment is 600W;

[0077] (2) using a rotary evaporator to rotary evaporate the first mixed system, collecting the solids after rotary evaporation, grinding them, and then transferring them to a tube furnace or a muffle furnace for calcination;

[0078] The vacuum pressure of the rotary evaporation is 0.1 MPa; the oil bath temperature of the rotary evaporation is 120° C.; the rotation speed of the rotary evaporation is 60 r / min; the calcination temperature is 200° C., and the calcination time is 4 h.

[0079] Example 6

[0080] The liquid-phase ultrasonic preparation method of a solid electrolyte is the same as in Example 1, except that the ultrasonic treatment time is 1 hour, the power of the ultrasonic equipment used for ultrasonic treatment is 400W, the vacuum pressure of the rotary evaporation is 0.12 MPa, the oil bath temperature of the rotary evaporation is 110°C, the rotation speed of the rotary evaporation is 50 r / min, the calcination temperature is 200°C, and the calcination time is 4 hours.

[0081] Example 7

[0082] The liquid phase ultrasonic preparation method of the solid electrolyte is the same as that of Example 1 except that the ultrasonic treatment time is 6 hours.

[0083] Example 8

[0084] The liquid-phase ultrasonic preparation method of a solid electrolyte is the same as in Example 1, except that the ultrasonic treatment time is 10 hours, the power of the ultrasonic equipment used for ultrasonic treatment is 800W, the vacuum pressure of the rotary evaporation is 0.08 MPa, the oil bath temperature of the rotary evaporation is 130°C, the rotation speed of the rotary evaporation is 70 r / min, the calcination temperature is 200°C, and the calcination time is 4 hours.

[0085] Example 9

[0086] Liquid-phase ultrasonic preparation method of solid electrolyte, except that halide metal salt and halide lithium salt are matched in the following manner, other conditions are the same as in Example 1:

[0087] Method 1: The halide metal salt is indium bromide, and the halide lithium salt is lithium bromide;

[0088] Method 2: The halide metal salt is indium iodide, and the halide lithium salt is lithium iodide;

[0089] Method 3: the halide metal salt is yttrium fluoride, and the halide lithium salt is lithium fluoride;

[0090] Method 4: the halide metal salt is scandium iodide, and the halide lithium salt is lithium iodide;

[0091] Method 5: The halide metal salt is yttrium bromide, and the halide lithium salt is lithium bromide.

[0092] Comparative Example 1

[0093] The preparation method of the solid electrolyte is the same as that of Example 1 except that methanol is used as the solvent and ultrasonic treatment is not used.

[0094] Comparative Example 2

[0095] The preparation method of the solid electrolyte is the same as that of Example 1 except that ethanol is used as the solvent and ultrasonic treatment is not used.

[0096] Experimental example

[0097] An AC impedance meter was used to test the conductivity of the solid electrolytes obtained in Examples 1 to 8 and Comparative Examples 1 to 2. The solid electrolytes of each embodiment and comparative example were pressed into sheets, specifically including: placing the solid electrolyte powder between two stainless steel cylindrical clamps with a diameter of 10 mm, applying a pressure of 3 tons, and pressing the solid electrolyte powder into an electrolyte sheet with a thickness of 0.6 mm. All processes were carried out in a glove box at a temperature of 273 K. The conductivity test results of the solid electrolytes of Examples 1 to 8 and Comparative Examples 1 to 2 are shown in Table 1. Due to the different properties of different materials, different material systems will have different conductivity limits. The conductivity of different materials is determined by the crystal structure of the material. The orthorhombic structure has a higher conductivity than the body-centered cubic structure and the face-centered cubic structure, and different materials have different crystal structures, resulting in different conductivity limits.

[0098] Table 1 Conductivity of solid electrolytes

[0099]

[0100]

[0101] As can be seen from Table 1, the present invention uses non-polar solvents such as dichloroethane, toluene, cyclohexane, n-ethane and isooctane to obtain a halide solid electrolyte with excellent electrical conductivity. Among them, dichloroethane is used as a dispersant to disperse the precursor powder material. The halide solid electrolyte obtained under the same ultrasonic conditions and the same calcination conditions has higher electrical conductivity.

[0102] Comparative Example 1, using the polar solvent methanol, and Comparative Example 2, using the formulation solvent ethanol, produced halide solid electrolytes with low conductivity. They also contained a large amount of impurities, particularly the complexation of the metal cations in the material by the protonated and dissociated polar functional groups, making solvent removal during rotary evaporation extremely difficult.

[0103] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid phase ultrasonic preparation method for a solid electrolyte, characterized in that: The following steps are involved: Mixing a halide metal salt, a halide lithium salt, and a non-polar solvent and performing ultrasonic treatment to obtain a first mixed system; performing rotary evaporation on the first mixed system, collecting the solid after rotary evaporation, and calcining; The ultrasonic treatment time is 0.1~48h, and the ultrasonic treatment power is 10~1000W; The vacuum pressure of the rotary evaporation is 0.08-0.12 MPa; the temperature of the rotary evaporation is 110-130° C.; the speed of the rotary evaporation is 50-70 r / min; The temperature of the ultrasonic treatment is 25-60°C; The ultrasonic treatment time is 0.5 to 10 hours; the ultrasonic treatment power is 400 to 800W; The non-polar solvent includes at least one of benzene, carbon tetrachloride, isooctane, toluene, dichloromethane, n-hexane, cyclohexane, heptane and liquid paraffin.

2. The liquid phase ultrasonic preparation method of a solid electrolyte according to claim 1, characterized in that: The temperature of the ultrasonic treatment is 25-50°C.

3. The liquid phase ultrasonic preparation method of a solid electrolyte according to claim 1, characterized in that: The halide metal salt includes at least one of indium chloride, indium bromide, indium iodide, indium fluoride, yttrium chloride, yttrium bromide, yttrium iodide, yttrium fluoride, scandium chloride, scandium bromide, scandium iodide, scandium fluoride and MX3; wherein M is selected from Tb, Dy, Ho, Er, Tm, Yb or Lu, and X is selected from Cl, Br, I or F.

4. The liquid phase ultrasonic preparation method of a solid electrolyte according to claim 1, characterized in that: The halide lithium salt includes at least one of lithium chloride, lithium bromide, lithium iodide and lithium fluoride.

5. The liquid phase ultrasonic preparation method of a solid electrolyte according to claim 1, characterized in that: Contains at least one of the following features (1) to (2): (1) The molar ratio of the lithium halide salt to the metal halide salt is (2.5-3.5): (0.8-1.2); (2) The volume ratio of the total mass of the halide lithium salt and the halide metal salt to the non-polar solvent is (1-100) g: (5-200) mL.

6. The liquid phase ultrasonic preparation method of a solid electrolyte according to claim 1, characterized in that: Contains at least one of the following features (1) to (2): (1) collecting the solids after rotary evaporation, grinding them to a particle size D50 < 100 μm, and then calcining them; (2) The calcination temperature is 60-500°C, and the calcination time is 1-12 hours.

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