Halide solid electrolyte and preparation method and application thereof

Abstract

The invention discloses a halide solid electrolyte and a preparation method and application thereof.The preparation method comprises the steps that a lithium source and an M source are added into a solvent according to the proportion and stirred, and a mixed solution is obtained; performing microwave treatment on the mixed solution to obtain a precursor material; the precursor material is subjected to heat treatment in vacuum to obtain the halide solid electrolyte LiaMZb, M is selected from one or more of group III metals, Z is selected from one or more of C1, Br, I and F, a is equal to 1-10, and b is equal to 1-10. The halide solid electrolyte is prepared through a microwave reaction method, the preparation time can be effectively shortened, the reaction energy consumption can be effectively reduced, and the prepared halide solid electrolyte has high ionic conductivity, low powder particle size and excellent electrochemical performance.

Description

Technical Field

[0001] The present application relates to the technical field of battery materials, and in particular to a halide solid electrolyte and a preparation method and application thereof. Background Art

[0002] Since its commercialization, lithium-ion secondary batteries have developed rapidly due to their advantages such as high energy density and long service life. However, the lithium-ion batteries commonly used at present contain flammable organic electrolytes, so there are serious safety hazards. In recent years, the frequent safety accidents in liquid-phase lithium-ion power batteries have greatly restricted the further use of this system. The use of non-flammable inorganic solid materials as lithium-ion battery electrolytes can not only eliminate the safety hazards caused by organic electrolyte leakage and internal thermal runaway of the battery during the use of the battery, but also can be used under extreme conditions such as high temperature and low temperature, further enhancing the value of lithium secondary batteries and expanding their application areas. Therefore, the research and development of inorganic solid electrolytes with high stability and high lithium ion conductivity is the key to the development of lithium secondary batteries with high safety.

[0003] Developing all-solid-state batteries to replace liquid batteries is one of the most effective ways to solve their safety performance and meet the needs of higher energy density. The so-called all-solid-state batteries use solid electrolytes instead of traditional liquid electrolytes. Therefore, solid electrolyte materials have become the top priority of all-solid-state development. Currently, commonly used electrolyte materials mainly include sulfide electrolytes, polymer electrolytes, oxide electrolytes, halide electrolytes, etc.

[0004] The halide solid electrolytes developed in recent years are considered to be one of the most promising candidate materials for solid-state batteries. Compared with oxide solid electrolytes, halide solid electrolytes are relatively light and show better mechanical flexibility. Compared with sulfide solid electrolytes, the radius of monovalent halogen ions is larger than that of divalent sulfur elements, and the interaction force with lithium ions is weak, which makes the lithium ion mobility of halide solid electrolytes high, deformable, and mechanically soft. In addition, the electrochemical window of halide solid electrolytes is wide and can be matched with high-voltage positive electrodes. At present, the preparation methods of halide solid electrolytes mainly include solid-phase mechanical method and liquid-phase method. The solid-phase mechanical method is easy to operate, but the reaction time is long, the energy consumption is high, and the size of the synthesized electrolyte particles is large; the liquid-phase method has a short synthesis time and low energy consumption, but the ionic conductivity of the obtained solid electrolyte is low. Therefore, how to obtain halide solid electrolytes with high ionic conductivity and low particle size through a simple and efficient preparation method is a problem that needs to be solved at present. Summary of the invention

[0005] In view of the above problems in the prior art, the present application provides a halide solid electrolyte and a preparation method and application thereof, and prepares a halide solid electrolyte with high ionic conductivity and low particle size by microwave reaction method. The specific technical scheme is as follows:

[0006] On the one hand, the present application provides a method for preparing a halide solid electrolyte, characterized in that the preparation method comprises:

[0007] Adding the lithium source and the M source into the solvent according to a proportion, stirring, and obtaining a mixed solution;

[0008] subjecting the mixed solution to microwave treatment to obtain a precursor material;

[0009] The precursor material is heat treated in vacuum to obtain a halide solid electrolyte Li a Z b ;

[0010] Wherein, M is selected from one or more of Group III metals, Z is selected from one or more of Cl, Br, I and F, a=1-10, b=1-10.

[0011] In a possible implementation, the lithium source includes one or more of LiCl, LiBr, LiI and LiF.

[0012] In a possible implementation, the M source includes one or more of InC l3, YC l3, YbC l3, ZrC l4, AlC l3 and FeC l3.

[0013] In a possible implementation manner, the molar ratio of the lithium source to the M source is 1-10:1-10.

[0014] In a possible implementation manner, the solvent is a mixture of water and an organic solvent, and the organic solvent includes at least one of ethanol, isopropanol, methanol, ethylene glycol, acetone, and tetrahydrofuran.

[0015] In a possible implementation manner, the microwave treatment satisfies at least one of the following characteristics:

[0016] The temperature of the microwave treatment is 100-200°C;

[0017] The microwave treatment time is 1-30 min.

[0018] In a possible implementation manner, the heat treatment satisfies at least one of the following characteristics:

[0019] The temperature of the heat treatment is 100-400°C;

[0020] The heat treatment time is 1-4h.

[0021] On the other hand, the present application provides a halide solid electrolyte obtained by the above-mentioned preparation method.

[0022] In a possible implementation manner, the ion conductivity of the halide solid electrolyte is greater than or equal to 1.6 mS / cm, and the particle size of the halide solid electrolyte is 2-10 μm.

[0023] On the other hand, the present application provides a solid-state battery, comprising a halide solid electrolyte obtained by the above-mentioned preparation method.

[0024] Based on the above technical solution, this application has the following beneficial effects:

[0025] 1. The present application treats a mixed solution of a raw material and a solvent by microwaves to obtain a precursor material, and heat-treats the precursor material in a vacuum to obtain a halide solid electrolyte. The preparation method proposed in the present application is simple to operate, and can greatly shorten the reaction time, effectively reduce the reaction energy consumption, and is conducive to the mass production of halide solid electrolytes; and the microwave treatment method can effectively reduce the particle size of the halide solid electrolyte, which is conducive to improving its ionic conductivity.

[0026] 2. The preparation method proposed in this application is universal for the preparation of halide solid electrolytes, and can prepare halide solid electrolytes that meet application requirements by adjusting the selection of raw materials and the ratio of raw materials.

[0027] 3. The halide solid electrolyte obtained by the method of the present application is applied in solid-state batteries, which can greatly improve the conductivity of solid-state battery electrodes, help improve the mobility of lithium ions, and thus improve the electrochemical capacity, rate performance and cycle stability of solid-state batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 : A SEM image of a halide solid electrolyte provided in Example 1 of the present application;

[0030] Figure 2 : SEM image of another halide solid electrolyte provided in Comparative Example 1 of the present application;

[0031] Figure 3: SEM image of another halide solid electrolyte provided in Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0033] For the following defined terms, these definitions shall apply unless a different definition is given in the claims or elsewhere in this specification. All numerical values, whether or not explicitly indicated, are defined herein as modified by the term "about". The term "about" generally refers to a numerical range that a person of ordinary skill in the art considers to be equivalent to the stated values ​​to produce substantially the same properties, functions, results, etc. A numerical range indicated by a lower value and a higher value is defined to include all numerical values ​​included in the numerical range and all subranges included in the numerical range.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0035] The following describes a method for preparing a halide solid electrolyte provided in an embodiment of the present application. The order of steps listed in the embodiment is only one way of executing the steps among many steps and does not represent the only execution order. The preparation method comprises:

[0036] S1: Under a protective atmosphere, weigh a lithium source and an M source, add the lithium source and the M source to a solvent according to a ratio, and stir to obtain a mixed solution.

[0037] Specifically, the protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton, and xenon to prevent the lithium source and the M source from contacting with air and to prevent the raw materials from being oxidized to generate impurities.

[0038] In some embodiments, the lithium source includes one or more of LiCl, LiBr, LiI and LiF, which is used to provide conductive Li ions in the halide solid electrolyte and can be dissolved in water and / or organic solvents, which is conducive to uniform mixing and sufficient reaction with the M source in subsequent steps.

[0039] In some embodiments, the M source includes one or more of InCl3, YCl3, YbCl3, ZrCl4, AlCl3 and FeCl3, which can be dissolved in water and / or organic solvents to ensure the uniformity of dispersion of each component in the mixed solution, thereby improving the mixing uniformity of the lithium source and the M source, which is beneficial to the full reaction of the raw materials in the subsequent steps.

[0040] In some embodiments, the molar ratio of the lithium source to the M source is 1-10:1-10; it can be understood that the molar ratio of the lithium source to the M source can be any point value in 1-10:1-10; illustratively, the molar ratio of the lithium source to the M source is 1:1, 1:5, 1:10, 5:1, 10:1, etc. In this way, the molar ratio of the lithium source to the M source is controlled within the above-mentioned ratio range, and different halide solid electrolytes can be prepared by changing the raw material ratio. Furthermore, according to specific application requirements, changing the selection of raw materials and / or the ratio of raw materials can adjust the ionic conductivity and stability of the prepared halide solid electrolyte to meet different application requirements.

[0041] In some embodiments, the solvent is a mixture of water and an organic solvent. The addition of an organic solvent can lower the boiling point of the mixture, which is beneficial to the removal of the solvent during the microwave treatment process, making the solvent volatilization process less time-consuming, thereby improving the efficiency of the microwave treatment; and the lithium source and the M source can be evenly distributed in the liquid phase, making it easier to obtain a precursor material with uniform grain size after crystallization.

[0042] Specifically, the organic solvent includes at least one of ethanol, isopropanol, methanol, ethylene glycol, acetone, and tetrahydrofuran.

[0043] S2: placing the above mixed solution in a microwave reactor for microwave treatment to obtain a precursor material.

[0044] Among them, compared with the currently known solid-phase mechanical method and liquid-phase method, the microwave treatment method is simpler to operate and less time-consuming. It can provide the energy required for solvent volatilization while meeting safety requirements, which is beneficial to reducing reaction energy consumption. Microwave treatment is also beneficial for obtaining halide solid electrolytes with high ionic conductivity and low powder particle size.

[0045] In some embodiments, the temperature of the microwave treatment is 100-200°C; it can be understood that the temperature of the microwave treatment can be any point value in 100-200°C; illustratively, the temperature of the microwave treatment is 100°C, 120°C, 150°C, 170°C, 200°C, etc. Preferably, the temperature of the microwave treatment is 140-160°C. In this way, the temperature of the microwave treatment is controlled within the above range, and a pure powdered precursor material can be obtained. If the temperature of the microwave treatment exceeds the above range, the temperature will be too high and oxide impurities will be generated, and the high temperature will promote the increase of the particle size of the powder particles, resulting in a decrease in ionic conductivity; if the temperature of the microwave treatment is lower than the above range, the free water in the mixed solution cannot be completely removed, and the raw material reaction is incomplete, which affects the quality of the prepared halide solid electrolyte and reduces the yield of the halide solid electrolyte.

[0046] Specifically, the time of microwave treatment is 1-30min; it can be understood that the time of microwave treatment can be any point value in 1-30min; illustratively, the time of microwave treatment is 1min, 10min, 15min, 25min, 30min, etc. Preferably, the time of microwave treatment is 5-10min. In this way, the time of microwave treatment is controlled within the above range, which can effectively remove free water in the mixed solution and avoid excessive reaction of raw materials to increase the particle size of powder. Compared with the solid phase mechanical method and the liquid phase method, the microwave treatment method can prepare the precursor material of the halide solid electrolyte in a shorter time, which is conducive to reducing the preparation time of the halide solid electrolyte and the energy consumption required for preparation, so that the preparation method is suitable for mass production.

[0047] Preferably, the temperature of the microwave treatment is set to 150° C. and the time of the microwave treatment is set to 10 min. Under this condition, the mixed solution can be dehydrated in a relatively short time and a pure precursor material with a small powder particle size can be obtained.

[0048] In some embodiments, the microwave treatment process is carried out in a vacuum environment or a protective gas atmosphere to prevent the raw materials from coming into contact with air during the microwave treatment process, thereby preventing the raw materials from combining with water molecules and oxygen atoms in the air, thereby avoiding incomplete dehydration or the generation of oxide impurities.

[0049] S3: placing the above-mentioned precursor material in a vacuum atmosphere furnace for heat treatment to obtain a halide solid electrolyte.

[0050] Heat treatment of precursor materials can effectively remove crystal water. The presence of crystal water will reduce the chemical stability of the halide solid electrolyte, especially in high temperature or humid environment. Crystal water may cause electrolyte decomposition, thereby affecting the long-term stability of the electrolyte; and the presence of crystal water will interfere with the migration path of lithium ions and hinder the rapid transmission of lithium ions, thereby reducing the ionic conductivity of the halide solid electrolyte.

[0051] In some embodiments, the temperature of the heat treatment is 100-400°C; it can be understood that the temperature of the heat treatment can be any point value in the range of 100-400°C; illustratively, the temperature of the microwave treatment is 100°C, 150°C, 200°C, 300°C, 400°C, etc. Preferably, the temperature of the heat treatment is 180-220°C. In this way, by controlling the heat treatment temperature within the above range, the crystal water in the precursor material can be effectively removed, and the ionic conductivity and chemical stability of the halide solid electrolyte can be reduced due to insufficient dehydration, thereby increasing the internal energy loss of the battery and affecting the efficiency and performance of the battery.

[0052] Specifically, the heat treatment time is 1-4h; it can be understood that the heat treatment time can be any point value in 1-4h; illustratively, the heat treatment time is 1h, 1.5h, 2h, 3h, 4h, etc. Preferably, the heat treatment time is 1.8-2.2h. In this way, the heat treatment time is controlled within the above range, which can effectively remove the crystal water and is conducive to the preparation of a pure halide solid electrolyte with high ionic conductivity and low particle size.

[0053] Preferably, the heat treatment temperature is set to 200° C. and the heat treatment time is set to 2 hours. Under this condition, the crystal water in the precursor material can be effectively removed to prepare a halide solid electrolyte with a low powder particle size and high ionic conductivity.

[0054] In some embodiments, the vacuum is continuously pumped to -0.1 MPa during the heat treatment process to ensure that the heat treatment process is carried out in a vacuum environment, thereby preventing the precursor material from coming into contact with the air and then reacting with water molecules and oxygen atoms in the air to generate impurities, which is beneficial to obtaining a pure halide solid electrolyte material.

[0055] The present application also provides a halide solid electrolyte, which is prepared by the preparation method in the above embodiment, and the chemical formula of the halide solid electrolyte is Li a Z b, wherein M is selected from one or more of the group III metals, Z is selected from one or more of Cl, Br, I and F, a=1-10, b=1-10. It can be understood that a can take any value from 1-10, b can take any value from 1-10; illustratively, it is equal to 1, 2.5, 5, 7.5, 10, etc., and b is equal to 1, 2.5, 5, 7.5, 10, etc. Wherein, the values ​​of a and b depend on the molar ratio of the lithium source and the M source in the preparation process of the halide solid electrolyte, that is, in the preparation process of the halide solid electrolyte, the halide solid electrolyte required for the application can be obtained by adjusting the molar ratio of the lithium source and the M source. Exemplarily, when the reaction raw materials are LiCl and InCl3, and the molar ratio of LiCl and InCl3 is 3:1, the prepared halide solid electrolyte is Li3InCl6; Exemplarily, when the reaction raw materials are LiCl, ZrCl4 and AlCl3, and the molar ratio of LiCl, ZrCl4 and AlCl3 is 2.3:0.7:0.3, the prepared halide solid electrolyte is Li 2.3 Zr 0.7 A l 0.3 C l6.

[0056] Specifically, the ion conductivity of the halide solid electrolyte prepared by the preparation method in the above embodiment is greater than or equal to 1.6 mS / cm, and the particle size of the halide solid electrolyte is 2-10 μm. When the halide solid electrolyte has a low powder particle size and high ion conductivity, the gap between the halide solid electrolyte particles is reduced, which is conducive to improving the transmission efficiency of lithium ions and providing more lithium ions, thereby improving the electrochemical performance of the solid-state battery containing the halide solid electrolyte.

[0057] Preferably, the ion conductivity of the halide solid electrolyte prepared by the preparation method in the above embodiment is greater than or equal to 2 mS / cm, and the particle size of the halide solid electrolyte is 2-6 μm.

[0058] On the other hand, the present application also provides a solid-state battery, comprising the halide solid electrolyte as described above, or comprising a halide solid electrolyte prepared by the preparation method of the halide solid electrolyte as described above.

[0059] In some exemplary embodiments, the halide solid electrolyte is present in the positive electrode plate of the solid-state battery; in other exemplary embodiments, the halide solid electrolyte can be present in the solid electrolyte membrane of the solid-state battery; in other exemplary embodiments, both the positive electrode plate and the solid electrolyte membrane of the solid-state battery can include the halide solid electrolyte to further improve the performance of the solid-state battery and meet the performance requirements of different solid-state batteries, with a wide range of applications.

[0060] The following is an introduction to the specific embodiments of the present application in conjunction with the above-mentioned halide solid electrolyte, its preparation method and application. The following embodiments describe the technical solution of the present application in more detail, and these embodiments are only for illustrative purposes, because various modifications and changes within the scope of the disclosure of the present application are obvious to those skilled in the art. The reagents used in the embodiments can be obtained commercially or synthesized according to conventional methods, and can be used directly without further treatment, and the instruments and devices used in the embodiments can be obtained commercially.

[0061] Example 1

[0062] This embodiment provides a halide solid electrolyte, which is prepared by the following steps:

[0063] 1. In a glove box filled with protective gas, weigh LiCl and InCl3 powders at a molar ratio of 3:1;

[0064] 2. Add the weighed powder to a mixed solution of appropriate amounts of deionized water and ethanol in a fume hood, and stir until the powder is completely dissolved to obtain a mixed solution;

[0065] 3. The mixed solution was transferred to a microwave reactor, and the microwave treatment temperature was set to 150° C. and the microwave treatment time was set to 10 min. After the reaction was completed, a precursor material was obtained;

[0066] 4. The precursor material is heat treated in a vacuum atmosphere furnace at a temperature of 200°C for 2 hours. During the heat treatment, the vacuum is continuously drawn to -0.1 MPa to finally obtain the halide solid electrolyte material Li3I nC l6.

[0067] Furthermore, the halide solid electrolyte obtained above is used to prepare the positive electrode sheet, and the specific steps are as follows:

[0068] 1. Weigh 5.6 g of NMC811 positive electrode material and 1.372 g of the halide solid electrolyte powder prepared above into a ball mill, add 50 g of zirconia balls with a diameter of 2 mm, and mill at a speed of 300 rpm for 30 min to obtain a mixed material of the positive electrode material and the halide solid electrolyte.

[0069] 2. Add 0.014g of conductive carbon and continue ball milling. Take out the milled composite material and add 0.014g of polytetrafluoroethylene to grind for 60 minutes to obtain a composite positive electrode block.

[0070] 3. Roll the composite positive electrode block, set the upper roller temperature of the roller press to 90°C and the lower roller temperature to 100°C, until a pole piece with a thickness of 85 μm is obtained;

[0071] 4. Roll-compound the above-mentioned electrode sheet with the carbon-coated aluminum foil to finally obtain the positive electrode sheet.

[0072] Example 2

[0073] This embodiment provides a halide solid electrolyte, and the same points as those in Example 1 are not repeated here. The difference from Example 1 is that: in a glove box into which a protective gas is introduced, LiCl and YCl3 powders are weighed in a molar ratio of 3:1; and finally the halide solid electrolyte prepared is Li3YbCl6.

[0074] Furthermore, the halide solid electrolyte Li3YC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the above-mentioned embodiment 1 and are not described in detail.

[0075] Example 3

[0076] This embodiment provides a halide solid electrolyte. The similarities with Example 1 are not repeated here. The difference from Example 1 is that: in a glove box into which a protective gas is introduced, LiCl and YbCl3 powders are weighed in a molar ratio of 3:1; and finally the halide solid electrolyte prepared is Li3YbCl6.

[0077] Furthermore, the halide solid electrolyte Li3YbC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned embodiment 1 and are not described in detail.

[0078] Example 4

[0079] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that: in a glove box into which a protective gas is introduced, LiCl and ZrCl4 powders are weighed in a molar ratio of 2:1; and the halide solid electrolyte finally prepared is Li3YbCl6.

[0080] Furthermore, the halide solid electrolyte Li2YbC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0081] Example 5

[0082] This embodiment provides a halide solid electrolyte. The same points as those in Embodiment 1 are not repeated here. The difference between this embodiment and Embodiment 1 is that: in a glove box filled with protective gas, LiCl, ZrCl4 and AlCl3 powders are weighed in a molar ratio of 2.3:0.7:0.3; and finally, a halide solid electrolyte is prepared as LiCl. 2.3 Zr0.7 A l 0.3 C l6.

[0083] Furthermore, the halide solid electrolyte Li obtained above is used 2.3 Zr 0.7 A l 0.3 C16 is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the above-mentioned embodiment 1 and are not described in detail.

[0084] Example 6

[0085] This embodiment provides a halide solid electrolyte, and the same points as those in Embodiment 1 are not repeated here. The difference between this embodiment and Embodiment 1 is that: in a glove box filled with protective gas, LiCl, ZrCl4 and FeCl3 powders are weighed in a molar ratio of 2.25:0.75:0.25; and finally, a halide solid electrolyte is prepared as Li 2.25 Zr 0.75 Fe 0.25 C l6.

[0086] Further, the halide solid electrolyte Li obtained above is used 2.25 Zr 0.75 Fe 0.25 C16 is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the above-mentioned embodiment 1 and are not described in detail.

[0087] Example 7

[0088] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that: the weighed powder is added to a mixed solution of appropriate amounts of deionized water and isopropanol in a fume hood, and stirred until the powder is completely dissolved to obtain a mixed solution; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0089] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0090] Example 8

[0091] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that: the weighed powder is added to a mixed solution of appropriate amounts of deionized water and methanol in a fume hood, and stirred until the powder is completely dissolved to obtain a mixed solution; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0092] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0093] Example 9

[0094] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that: the weighed powder is added to a mixed solution of appropriate amounts of deionized water and ethylene glycol in a fume hood, and stirred until the powder is completely dissolved to obtain a mixed solution; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0095] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0096] Example 10

[0097] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that: the weighed powder is added to a mixed solution of appropriate amounts of deionized water and acetone in a fume hood, and stirred until the powder is completely dissolved to obtain a mixed solution; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0098] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0099] Embodiment 11

[0100] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that: the weighed powder is added to a mixed solution of an appropriate amount of deionized water and tetrahydrofuran in a fume hood, and stirred until the powder is completely dissolved to obtain a mixed solution; and finally the halide solid electrolyte prepared is Li3I nC l6.

[0101] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0102] Example 12

[0103] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that the temperature of the microwave treatment is set to 100° C.; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0104] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0105] Embodiment 13

[0106] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that the temperature of the microwave treatment is set to 200° C.; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0107] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0108] Embodiment 14

[0109] This embodiment provides a halide solid electrolyte. The similarities with Example 1 are not repeated here. The difference from Example 1 is that the microwave treatment time is set to 5 minutes; and the halide solid electrolyte finally prepared is Li3InC l6.

[0110] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0111] Embodiment 15

[0112] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that the microwave treatment time is set to 30 minutes; and the halide solid electrolyte finally prepared is Li3I nC l6.

[0113] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0114] Example 16

[0115] This embodiment provides a halide solid electrolyte. The similarities with Example 1 are not repeated here. The difference from Example 1 is that the heat treatment temperature is set to 100° C. and the halide solid electrolyte finally prepared is Li3InC16.

[0116] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0117] Embodiment 17

[0118] This embodiment provides a halide solid electrolyte. The similarities with Example 1 are not repeated here. The difference from Example 1 is that the heat treatment temperature is set to 400°C; and the halide solid electrolyte finally prepared is Li3InC16.

[0119] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0120] Embodiment 18

[0121] This embodiment provides a halide solid electrolyte. The similarities with Example 1 are not repeated here. The difference from Example 1 is that the heat treatment time is set to 1 hour; and the halide solid electrolyte finally prepared is Li3I nCl6.

[0122] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0123] Embodiment 19

[0124] This embodiment provides a halide solid electrolyte, and the similarities with Example 1 are not repeated here. The difference from Example 1 is that the heat treatment time is set to 4 hours; and the halide solid electrolyte finally prepared is Li3I nC16.

[0125] Comparative Example 1

[0126] This comparative example provides a halide solid electrolyte, which is prepared by solid phase mechanical ball milling, and the specific steps are as follows:

[0127] 1. In a glove box filled with protective gas, weigh LiCl and InCl3 powders in a molar ratio of 3:1.

[0128] 2. Add the weighed powder into a ball mill, add zirconia balls with a diameter of 10 mm, the mass ratio of zirconia balls to powder is 10:1, set the ball mill speed to 250 rpm, and the ball milling time to 20 h to obtain the precursor material;

[0129] 3. The precursor material is heat treated in a vacuum atmosphere furnace at a temperature of 200°C for 2 hours. During the heat treatment, the vacuum is continuously drawn to -0.1 MPa to finally obtain the halide solid electrolyte material Li3I nC l6.

[0130] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0131] Comparative Example 2

[0132] This comparative example provides a halide solid electrolyte, which is prepared by a liquid phase method, and the specific steps are as follows:

[0133] 1. In a glove box filled with protective gas, weigh LiCl and InCl3 powders at a molar ratio of 3:1;

[0134] 2. Add the weighed powder to an appropriate amount of deionized water in a fume hood, stir until completely dissolved, and then use a vacuum oven to dry for 48 hours to obtain a precursor material;

[0135] 3. The precursor material is heat treated in a vacuum atmosphere furnace at a temperature of 200°C for 2 hours. During the heat treatment, the vacuum is continuously drawn to -0.1 MPa to finally obtain the halide solid electrolyte material Li3I nC l6.

[0136] Furthermore, the halide solid electrolyte Li3I nC16 obtained above is used to prepare the positive electrode sheet. The specific steps and parameters used are consistent with those in the aforementioned Example 1 and are not described in detail.

[0137] The ion conductivity of the halide solid electrolyte obtained in the above embodiment and comparative example was tested using a Swiss Metrohm PGSTAT302 electrochemical workstation with a test frequency range of 10 MHz-1 Hz and a bias voltage of 10 mV. During the test, 200 mg of halide solid electrolyte powder was weighed and pressed into sheets using a mold with a diameter of 10 mm at a pressure of 350 MPa, with stainless steel as a blocking electrode. According to the conductivity calculation formula σ=L / (R*S), L is the thickness of the sample, R is the total impedance, and S is the effective area of ​​contact between the sample and the electrode, the ion conductivity is calculated.

[0138] The positive electrode sheets made of the halide solid electrolyte obtained in the above embodiments and comparative examples were tested. The prepared positive electrode sheets were cut into small discs with a diameter of 10 mm using a punching machine, and assembled into solid-state batteries with sulfide solid electrolyte membranes and lithium indium negative electrodes. The solid-state batteries were placed in a blue battery test system for electrochemical performance testing at a rate of 0.1C.

[0139] The following table 1 statistically records the test data in the embodiments and comparative examples:

[0140] Table 1

[0141]

[0142]

[0143] Referring to the test results in Table 1, combined with Examples 1-6, it can be seen that the preparation method provided in the present application can obtain a halide solid electrolyte that can meet different application requirements by selecting different reaction raw materials or changing the ratio of the lithium source and the M source in the reaction raw materials, and the prepared halide solid electrolytes have high ionic conductivity, and exhibit good charge and discharge performance and chemical stability when applied to solid-state batteries, which proves that the preparation method provided in the present application is universal for the preparation of halide solid electrolytes.

[0144] In combination with Example 1 and Examples 7-11, it can be seen that in the process of mixing raw materials, the same molar ratio of LiCl and InCl3 powders are dissolved in a mixture of different organic solvents and water, and a halide solid electrolyte Li3InCl6 with high ionic conductivity can be prepared, and the ionic conductivity of the halide solid electrolyte is greater than or equal to 1.66mS / cm, and the first-cycle discharge specific capacity of the prepared solid-state battery is above 196.5mAh / g, which proves that the change of the organic solvent will not affect the product performance.

[0145] In Example 1 and Examples 12-15, the main difference between the embodiments in the process of preparing the halide solid electrolyte is that the time and temperature of the microwave treatment are different. By comparison, it can be seen that the halide solid electrolyte Li3I nC l6 can be prepared in the above embodiments; in Example 1, when the microwave treatment temperature is 150°C and the time is 10 min, the halide solid electrolyte prepared has an ionic conductivity of 2.12 mS / cm; it is proved that within the microwave treatment time and temperature range provided in the present application, when the microwave treatment temperature is 100-200°C and the time is 5-30 min, appropriately increasing or decreasing the microwave treatment time and / or temperature can prepare a halide solid electrolyte with good conductivity, and the ionic conductivity of the halide solid electrolyte is greater than or equal to 1.75 mS / cm.

[0146] In Example 1 and Examples 16-19, the main difference between the embodiments in the process of preparing the halide solid electrolyte is the different time and temperature of the heat treatment. By comparison, it can be seen that the halide solid electrolyte Li3I nC l6 can be prepared in the above embodiments; when the heat treatment temperature in Example 1 is 200°C and the time is 2h, the prepared halide solid electrolyte has an ionic conductivity of 2.12mS / cm; within the heat treatment time and temperature range provided in the present application, when the heat treatment temperature is 100-400°C and the time is 1-4h, appropriately increasing or decreasing the heat treatment time and / or temperature can still effectively remove the crystallization water in the precursor material to obtain a halide solid electrolyte with an ionic conductivity greater than or equal to 1.82mS / cm.

[0147] In combination with Example 1 and Comparative Examples 1 and 2, it can be seen that compared with the solid-phase mechanical ball milling method and the liquid phase method, the microwave reaction method proposed in this application can prepare the precursor material in a shorter time, which is beneficial to reduce the energy consumption required for the preparation process, improve production efficiency, and is suitable for the mass production of halide solid electrolytes. Referring to the test data in Table 1, it can be seen that the ionic conductivity of the halide solid electrolytes prepared in Comparative Examples 1 and 2 is 1.32mS / cm and 1.49mS / cm, respectively. Compared with the halide solid electrolytes and solid-state batteries prepared in Comparative Examples 1 and 2, the halide solid electrolyte prepared by the microwave reaction method in Example 1 has a higher ionic conductivity. When the halide solid electrolyte is applied to a solid-state battery, the solid-state battery has a higher first-cycle discharge specific capacity and capacity retention rate, proving that the halide solid electrolyte provided in this application is applied to a solid-state battery and can effectively improve the electrochemical performance of the solid-state battery.

[0148] refer to Figure 1-3 It can be seen that the halide solid electrolyte prepared in Example 1 is granular and has a low particle size of 2-6μm, which is conducive to close contact between halide solid electrolyte particles, improves the conductivity of the pole piece, and thus improves the electrochemical performance of the solid-state battery. The halide solid electrolytes prepared by solid-phase mechanical ball milling and liquid phase methods in Comparative Examples 1 and 2 are irregular blocks, the block solid electrolytes are adhered to each other, and the block size distribution range is large. The particle size of some block solid electrolytes exceeds 30μm. The comparison proves that microwave treatment can effectively reduce the particle size of halide solid electrolytes.

[0149] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0150] What is described above are only some embodiments of the present application and are not intended to limit the present application. Those skilled in the art should understand that the present application may undergo various changes and improvements, and any modifications, equivalent substitutions and improvements made in accordance with the present application shall fall within the scope of protection required by the present application.

Claims

1. A method for preparing a halide solid electrolyte, characterized in that: The preparation method comprises: Adding the lithium source and the M source into the solvent according to a proportion, stirring, and obtaining a mixed solution; subjecting the mixed solution to microwave treatment to obtain a precursor material; The precursor material is heat treated in vacuum to obtain a halide solid electrolyte Li a Z b ; Wherein, M is selected from one or more of Group III metals, Z is selected from one or more of Cl, Br, I and F, a=1-10, b=1-10.

2. The preparation method according to claim 1, characterized in that: The lithium source includes one or more of LiCl, LiBr, LiI and LiF.

3. The preparation method according to claim 1, characterized in that: The M source includes one or more of InCl3, YCl3, YbCl3, ZrCl4, AlCl3 and FeCl3.

4. The preparation method according to any one of claims 1 to 3, characterized in that The molar ratio of the lithium source to the M source is 1-10:1-10.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The solvent is a mixture of water and an organic solvent, and the organic solvent includes at least one of ethanol, isopropanol, methanol, ethylene glycol, acetone, and tetrahydrofuran.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The microwave treatment satisfies at least one of the following characteristics: The temperature of the microwave treatment is 100-200°C; The microwave treatment time is 1-30 min.

7. The preparation method according to any one of claims 1 to 3, characterized in that: The heat treatment satisfies at least one of the following characteristics: The temperature of the heat treatment is 100-400°C; The heat treatment time is 1-4h.

8. A halide solid electrolyte, characterized in that: Obtained by the preparation method described in any one of claims 1 to 7.

9. The halide solid electrolyte according to claim 8, characterized in that The ion conductivity of the halide solid electrolyte is greater than or equal to 1.6 mS / cm, and the particle size of the halide solid electrolyte is 2-10 μm.

10. A solid-state battery, characterized in that: Comprising the halide solid electrolyte as described in any one of claims 8-9.

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