Oxyhalide solid electrolyte and preparation method thereof

Abstract

The invention discloses an oxyhalide solid electrolyte and a preparation method thereof, and the method comprises the following steps: respectively weighing LiOH, M2O5 and SOCl2 according to a molar ratio of 2: 1: (5 + x) to obtain preparation raw materials; wherein x ranges from 0 to 10, and M is Nb or Ta; putting the preparation raw materials and the ball-milling balls into a ball-milling tank, and carrying out ball-milling treatment for 1-50 hours, so as to obtain an initial product; the ball milling rotating speed corresponding to the ball milling treatment is 200-500 rpm; and carrying out heat treatment on the initial product at 80-400 DEG C to obtain the oxyhalide solid electrolyte Li2O2-MCl5, the heat treatment time is 1-20 hours. Cheap M2O5 is adopted as an M source, and cheap SOCl2 is added as a chlorinating agent to replace original high-cost MCl5, so that the preparation cost of the oxyhalide solid electrolyte is effectively reduced on the premise of not reducing the conductivity of a product, and large-scale application is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of all-solid-state batteries, and in particular to an oxyhalide solid electrolyte and a preparation method thereof. Background Art

[0002] In recent years, compared with halide solid electrolytes (conductivity <3mS / cm), oxyhalide solid electrolytes have higher conductivity, wider composition variation possibilities, isotropic ion conduction mechanism, and all-solid-state batteries using them have attracted increasing interest from researchers due to their potential high rate, high safety, and high specific energy characteristics. A typical example of oxyhalide solid electrolytes is the Li2O2-MCl5 (M=Ta / Nb) binary system, such as patents CN113015694B, CN116741935A, etc., or non-patent literature New Oxyhalide Solid Electrolytes with High Lithium Ionic Conductivity>10mScm -1 for All-Solid-State Batteries.

[0003] Non-patent literature New Oxyhalide Solid Electrolytes with High Lithium Ionic Conductivity>10mScm -1 for All-Solid-State Batteries proposed a component with the chemical formula of LiMOCl4 (M = Nb, Ta), and LiOH and MCl5 were selected for material selection. When M = Nb, the precursor material is a crystalline phase, and its crystalline phase conductivity after annealing is 10.4mS / cm; when M = Ta, the precursor material is an amorphous phase. For LiNbOCl4, there is no significant change in the XRD spectrum before and after annealing, only a slight increase in peak intensity and improved crystallinity after annealing. LiTaOCl4 is amorphous before annealing, and crystallizes after annealing, and the conductivity increases from 7.8mS / cm of amorphous to 12.4mS / cm of crystallized.

[0004] In addition to continuing to improve the ionic conductivity of Li2O2-MCl5 binary oxyhalide solid electrolyte, the current important research direction is to reduce the cost of this material to below the current generally accepted battery application threshold of 1 yuan / gram. Summary of the invention

[0005] The present application provides an oxyhalide solid electrolyte and a preparation method thereof. By adopting cheap M2O5 as the M source and adding cheap SOCl2 as the chlorinating agent to replace the original high-cost MCl5, the preparation cost of the oxyhalide solid electrolyte is effectively reduced without reducing the product conductivity, which is conducive to the large-scale application of the oxyhalide solid electrolyte.

[0006] On the one hand, the present application provides a method for preparing an oxyhalide solid electrolyte, the method comprising:

[0007] LiOH, M2O5, and SOCl2 are weighed respectively according to a molar ratio of 2:1:(5+x) to obtain a raw material for preparation; wherein x ranges from 0 to 10, and M is Nb or Ta;

[0008] The raw materials and the ball milling balls are placed in a ball milling jar for 1-50 hours to obtain an initial product; the ball milling speed corresponding to the ball milling treatment is 200-500 rpm;

[0009] The initial product is heat-treated at 80-400° C. to obtain the oxyhalide solid electrolyte Li2O2-MCl5; the heat treatment time is 1-20 hours; the oxyhalide solid electrolyte Li2O2-MCl5 is formed by the accumulation of a plurality of spherical oxyhalide solid electrolyte particles, and the particle size range of the oxyhalide solid electrolyte particles is 0.5-3 μm.

[0010] Further, the preparation raw material and the ball milling balls are placed in a ball milling jar for 1-50 hours to obtain an initial product, including:

[0011] Placing the raw material and the ball milling balls in the ball milling jar for ball milling to obtain a mixture of the initial product, the ball milling balls and by-products; the mass ratio of the raw material to the ball milling balls is 1:(1-50);

[0012] After the ball milling treatment is completed, the pressure relief valve of the ball milling tank is opened to separate the by-products to obtain a mixture of the initial product and the ball milling balls;

[0013] The initial product and the mixture of the ball milling balls are separated by using a sieve to obtain the initial product; the specification of the sieve is 20-50 meshes.

[0014] Further, the initial product is heat treated at 80-400° C. to obtain the oxyhalide solid electrolyte Li2O2-MCl5, comprising:

[0015] Heat treating the initial product at 80-400° C. for 0.5-1 h to obtain an intermediate product;

[0016] The intermediate product is further subjected to heat treatment at 80-400° C. for 0.5-19 h to obtain the oxyhalide solid electrolyte Li2O2-MCl5.

[0017] Furthermore, the by-products include SO2 gas and HCl gas.

[0018] Furthermore, in an X-ray diffraction test, characteristic peaks of the oxyhalide solid electrolyte Li2O2-MCl5 are located at 2θ=13.5°, 2θ=24-25° and 2θ=31-32°.

[0019] Furthermore, the yield of the oxyhalide solid electrolyte Li2O2-MCl5 is greater than or equal to 94%; the yield of the oxyhalide solid electrolyte Li2O2-MCl5 is positively correlated with the feed amount of SOCl2.

[0020] Furthermore, the ionic conductivity of the oxyhalide solid electrolyte Li2O2-MCl5 is 1.7-9.5 mS / cm.

[0021] Furthermore, the oxyhalide solid electrolyte particles include oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size, and the number of oxyhalide solid electrolyte particles of the first particle size is greater than that of oxyhalide solid electrolyte particles of the second particle size; the first particle size range is 0.5-2μm, and the second particle size range is 2.1-3μm.

[0022] On the other hand, an oxyhalide solid electrolyte is provided. The oxyhalide solid electrolyte is prepared by the above-mentioned preparation method.

[0023] On the other hand, an all-solid-state battery is provided, wherein the all-solid-state battery comprises the above-mentioned oxyhalide solid electrolyte.

[0024] The oxyhalide solid electrolyte and the preparation method thereof provided in the present application have the following technical effects:

[0025] The present application weighs LiOH, M2O5, and SOCl2 respectively according to a molar ratio of 2:1:(5+x) to obtain a preparation raw material; wherein, the range of x is 0-10, and M is Nb or Ta; the preparation raw material and ball milling balls are placed in a ball milling jar for 1-50 hours of ball milling treatment to obtain an initial product; the ball milling speed corresponding to the ball milling treatment is 200-500rpm; the initial product is heat-treated at 80-400°C to obtain an oxyhalide solid electrolyte Li2O2-MCl5; the heat treatment time is 1-20 hours; the oxyhalide solid electrolyte Li2O2-MCl5 is formed by the accumulation of multiple spherical oxyhalide solid electrolyte particles, and the particle size range of the oxyhalide solid electrolyte particles is 0.5-3μm. The present application adopts cheap M2O5 as the M source and adds cheap SOCl2 as the chlorinating agent to replace the original high-cost MCl5. Under the premise of not reducing the conductivity of the product, the preparation cost of the oxyhalide solid electrolyte is effectively reduced, which is conducive to the large-scale application of the oxyhalide solid electrolyte.

[0026] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions and advantages of the embodiments of this specification 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 paying creative work.

[0028] Figure 1 It is a schematic flow chart of a method for preparing an oxyhalide solid electrolyte provided in an embodiment of this specification;

[0029] Figure 2 is a schematic flow chart of a method for obtaining an initial product provided in an embodiment of this specification;

[0030] Figure 3 It is a schematic flow chart of a heat treatment method provided in an embodiment of this specification;

[0031] Figure 4 It is a molecular structure diagram of SOCl2 thionyl chloride provided in the examples of this specification;

[0032] Figure 5 is a scanning electron microscope image of an oxyhalide solid electrolyte provided in an embodiment of this specification;

[0033] Figure 6It is an XRD diffraction pattern of an oxyhalide solid electrolyte LiNbOCl4 provided in the embodiments of this specification;

[0034] Figure 7 It is an XRD diffraction pattern of an oxyhalide solid electrolyte LiTaOCl4 provided in the embodiments of this specification;

[0035] Figure 8 It is the XRD diffraction pattern of another oxyhalide solid electrolyte LiNbOCl4 provided in the embodiments of this specification;

[0036] Fig. 9 It is the XRD diffraction pattern of another oxyhalide solid electrolyte LiTaOCl4 provided in the examples of this specification;

[0037] Fig.10 This is a schematic diagram of the structure of an all-solid-state battery using an oxyhalide solid electrolyte Li2O2-MCl5 provided in an embodiment of this specification;

[0038] Fig.11 This is a conductivity change trend diagram of a LiNbOCl4 solid electrolyte prepared under the conditions of different x values ​​in a molar ratio of 2:1:(5+x) provided in an embodiment of this specification;

[0039] Fig.12 This is a comparison chart of raw material costs for synthesizing oxyhalide solid electrolyte Li2O2-MCl5 under different conditions provided in the examples of this specification. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] The following describes a method for preparing an oxyhalide solid electrolyte of the present application, specifically as follows Figure 1 As shown, the method may include:

[0042] S1: LiOH, M2O5 and SOCl2 are weighed respectively in a molar ratio of 2:1:(5+x) to obtain a preparation raw material; wherein x is in the range of 0-10, preferably 0.5, and M is Nb or Ta.

[0043] In the embodiment of the present application, LiOH, M2O5, and SOCl2 are used as raw materials for preparing an oxyhalide solid electrolyte, and the three raw materials are weighed respectively according to a molar ratio of 2:1:(5+x), where x ranges from 0 to 10, and M is Nb or Ta.

[0044] In the embodiments of the present application, Figure 4 As shown, Figure 4 This is the molecular structure diagram of SOCl2 thionyl chloride. Sulfonyl chloride is mainly used to manufacture acyl chloride compounds. Since thionyl chloride has the advantages of mild reaction conditions, good purity and high yield in synthesizing acyl chloride, it is widely used in industry. It is also used in the production of pesticides, medicines, dyes, etc. at a low price.

[0045] In the embodiment of the present application, cheap M2O5 is used as the M source, and cheap SOCl2 is added as the chlorinating agent to replace the original high-cost MCl5. Without changing the original general process flow and equipment and without reducing the conductivity of the product, the preparation cost of the Li2O2-MCl5 binary oxyhalide solid electrolyte is greatly reduced, which is conducive to the large-scale application of the material in batteries. The reaction formula is as follows:

[0046] 2LiOH+M2O5+5SOCl2→2LiMOCl4+5SO2↑+2HCl↑

[0047] In the embodiments of the present application, the SOCl2 chlorinating agent not only serves as a Cl source, but its liquid properties also contribute to the lubrication of the material during ball milling preparation, thereby improving the uniformity of raw material mixing and reaction, and improving the conductivity of the product; it also reduces the product residue on the surface of the ball milling balls and ball milling beads, thereby improving the yield.

[0048] S2: placing the prepared raw materials and ball milling balls in a ball milling jar for 1-50 hours to obtain an initial product; the ball milling speed corresponding to the ball milling treatment is 200-500 rpm.

[0049] Furthermore, the step of placing the raw materials and the ball milling balls in a ball milling jar for 1-50 hours to obtain the initial product may include:

[0050] S21: placing the raw material and the ball milling balls in the ball milling jar for ball milling to obtain a mixture of the initial product, the ball milling balls and by-products; the mass ratio of the raw material to the ball milling balls is 1:(1-50);

[0051] S22: after the ball milling treatment is completed, opening the pressure relief valve of the ball milling tank to separate the by-products to obtain a mixture of the initial product and the ball milling balls;

[0052] S23: using a sieve to separate the mixture of the initial product and the ball milling balls to obtain the initial product; the specification of the sieve is 20-50 mesh.

[0053] In an embodiment of the present application, after weighing the three raw materials separately, the prepared raw materials are obtained, and the prepared raw materials and ball milling balls are placed in a ball mill with a pressure relief valve for high-speed ball milling to obtain a mixture of initial product, ball milling balls and by-products. After stopping the ball milling, the pressure relief valve of the ball mill is opened to discharge the by-product gas. After no gas is discharged, the mixture of the initial product and the ball milling balls in the ball mill is transferred and separated using a sieve to obtain the initial product; wherein the specification of the sieve can be 20-50 mesh.

[0054] In the embodiments of the present application, the mass ratio of the preparation raw material to the ball milling balls can be in the range of 1:1 to 1:50, preferably 1:20; the ball milling time can be in the range of 1-50h, preferably 20h; the ball milling speed can be in the range of 200-500rpm, preferably 400rpm.

[0055] The embodiment of the present application induces a reaction through high-speed ball milling. The gas by-products generated by the reaction can be simply removed by opening the pressure relief valve. The ball milling balls can be effectively separated by a sieve to obtain the initial product. The reaction process is simple and is conducive to large-scale production.

[0056] Furthermore, the by-products include SO2 gas and HCl gas.

[0057] In the embodiment of the present application, the three raw materials LiOH, M2O5, and SOCl2 react under high-speed ball milling. In addition to generating LiMOCl4, two by-products, SO2 gas and HCl gas, are also generated. These two by-products can be removed by opening the pressure relief valve of the ball mill after stopping the ball milling. If some by-product gas still remains in the initial product, it can also be removed during heat treatment. Compared with other types of by-products, gas by-products are easier to remove, and the preparation process is simpler.

[0058] The gas by-products in the embodiments of the present application are easier to remove, making the overall preparation process simpler and more convenient, which is conducive to large-scale production.

[0059] S3: heat-treating the initial product at 80-400°C to obtain the oxyhalide solid electrolyte Li2O2-MCl5; the heat treatment time is 1-20h; the oxyhalide solid electrolyte Li2O2-MCl5 is formed by stacking a plurality of spherical oxyhalide solid electrolyte particles, and the particle size range of the oxyhalide solid electrolyte particles is 0.5-3μm.

[0060] Further, the heat treatment of the initial product at 80-400° C. to obtain the oxyhalide solid electrolyte Li2O2-MCl5 may include:

[0061] S31: heat treating the initial product at 80-400° C. for 0.5-1 h to obtain an intermediate product;

[0062] S32: Continue to heat treat the intermediate product at 80-400° C. for 0.5-19 h to obtain the oxyhalide solid electrolyte Li2O2-MCl5.

[0063] In an embodiment of the present application, after the initial product is separated, the initial product is heat treated to obtain the oxyhalide solid electrolyte Li2O2-MCl5; wherein the heat treatment temperature may be in the range of 80-400°C, and for M=Nb, the preferred heat treatment temperature is 100°C; for M=Ta, the preferred heat treatment temperature is 300°C; the heat treatment time may be in the range of 1-20h, and for M=Nb, the preferred heat treatment time is 3h; for M=Ta, the preferred heat treatment time is 15h.

[0064] In the embodiment of the present application, the heat treatment of the initial product at 80-400° C. to obtain the oxyhalide solid electrolyte Li2O2-MCl5 may also include:

[0065] Heat treating the initial product at 80-200° C. for 0.5-1 h to obtain an intermediate product;

[0066] The intermediate product is further heat treated at 200-400°C for 0.5-19h to obtain the oxyhalide solid electrolyte Li2O2-MCl5.

[0067] In an embodiment of the present application, the initial product can be heat treated at 80-400°C for 0.5-1h to obtain an intermediate product, and the intermediate product is further heat treated for 0.5-19h to obtain the oxyhalide solid electrolyte Li2O2-MCl5. The present application does not limit the number of heat treatments and the temperature and time of a single heat treatment.

[0068] The embodiment of the present application treats the initial product by heat treatment to obtain the final oxyhalide solid electrolyte Li2O2-MCl5. The heat treatment process is simple and can be adjusted in time according to the actual experimental progress. The overall preparation method is simple, and the preparation process is still simple and feasible while greatly reducing the raw material cost.

[0069] Furthermore, in an X-ray diffraction test, characteristic peaks of the oxyhalide solid electrolyte Li2O2-MCl5 are located at 2θ=13.5°, 2θ=24-25° and 2θ=31-32°.

[0070] In an embodiment of the present application, an XRD test is performed on the prepared oxyhalide solid electrolyte Li2O2-MCl5. In the XRD spectrum of Li2O2-MCl5, the positions of its characteristic peaks are located at 2θ=13.5°, 2θ=24-25° and 2θ=31-32°. There may be a slight shift in the position of the characteristic peaks, but their position range is still within the above-mentioned positions.

[0071] The embodiment of the present application can confirm that the final product is the oxyhalide solid electrolyte Li2O2-MCl5 through the diffraction peak position in the XRD test, which can effectively ensure the reaction accuracy.

[0072] Furthermore, the yield of the oxyhalide solid electrolyte Li2O2-MCl5 is greater than or equal to 94%; the yield of the oxyhalide solid electrolyte Li2O2-MCl5 is positively correlated with the feed amount of SOCl2.

[0073] In the embodiment of the present application, the yield of the oxyhalide solid electrolyte Li2O2-MCl5 obtained by the preparation method of the present application is greater than or equal to 94%, which is a high yield. According to the test data in Table 1, it can be found that the yield of the oxyhalide solid electrolyte Li2O2-MCl5 is positively correlated with the feeding amount of SOCl2. This is because the SOCl2 chlorinating agent as a Cl source is a liquid raw material, which helps the lubrication of the material during ball milling preparation, improves the uniformity of mixing and reaction of each raw material, effectively improves the conductivity of the product, and also reduces the surface residue of the product on the ball milling balls and ball milling beads, thereby further improving the yield.

[0074] In the examples of the present application, the liquid SOCl2 raw material is used to improve the uniformity of raw material mixing and reaction, improve the conductivity and yield of the product, and still have a high yield while reducing the raw material cost, indicating that the preparation method is highly feasible and is conducive to the large-scale application of Li2O2-MCl5 electrolyte materials.

[0075] Furthermore, the ionic conductivity of the oxyhalide solid electrolyte Li2O2-MCl5 is 1.7-9.5 mS / cm.

[0076] In the embodiments of the present application, Fig.11This is a conductivity change trend diagram of the LiNbOCl4 solid electrolyte prepared under the conditions of different x values ​​in the molar ratio of 2:1:(5+x) provided in the embodiment of the present application. The ionic conductivity of the oxyhalide solid electrolyte LiNbOCl4 ranges from 1.7 to 9.5 mS / cm. When the feed ratio changes, the conductivity of the obtained product will also be different. With the increase of SOCl2 thionyl chloride molecules, the conductivity shows a trend of first increasing and then decreasing. SOCl2 thionyl chloride has a boiling point of 80°C and is volatile. A slightly excess of raw materials helps the completeness of the reaction and the yield when discharging. When the liquid thionyl chloride is excessive, it is mixed with a gas and liquid mixture, and the solid material in the ball mill cannot effectively contact the ball mill, resulting in a decrease in the degree of reaction and thus a decrease in conductivity. Therefore, in order to obtain a product with high ionic conductivity, the amount of SOCl2 in the raw material can be controlled.

[0077] The examples of the present application show that the low-cost preparation method provided in the present application can prepare the oxyhalide solid electrolyte Li2O2-MCl5 with higher ionic conductivity, which helps to improve the performance of all-solid-state batteries.

[0078] Furthermore, the oxyhalide solid electrolyte particles include oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size, and the number of oxyhalide solid electrolyte particles of the first particle size is greater than that of oxyhalide solid electrolyte particles of the second particle size; the first particle size range is 0.5-2μm, and the second particle size range is 2.1-3μm.

[0079] In the embodiments of the present application, Figure 5 A scanning electron microscope image of an oxyhalide solid electrolyte provided in an embodiment of the present application, Figure 5 It can be seen that the oxyhalide solid electrolyte Li2O2-MCl5 is formed by the accumulation of multiple irregular spherical oxyhalide solid electrolyte particles, and the particle size range of the oxyhalide solid electrolyte particles is 0.5-3μm; wherein, the oxyhalide solid electrolyte particles include oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size, and the number of oxyhalide solid electrolyte particles of the first particle size is greater than that of oxyhalide solid electrolyte particles of the second particle size, the first particle size range is 0.5-2μm, and the second particle size range is 2.1-3μm, that is, the oxyhalide solid electrolyte particles with smaller particle sizes are relatively more, and are composed of Figure 5 It can be seen that the stacking of each oxyhalide solid electrolyte particle is also relatively uniform, which is conducive to providing sufficient channels for ion transport, obtaining an oxyhalide solid electrolyte with high ionic conductivity, and thus obtaining an all-solid-state battery with good performance.

[0080] The oxyhalide solid electrolyte prepared in the embodiment of the present application is formed by stacking a plurality of oxyhalide solid electrolyte particles, which can provide sufficient channels for ion transport and improve the ionic conductivity of the oxyhalide solid electrolyte.

[0081] In the embodiments of the present application, the particle size of the oxyhalide solid electrolyte particles can be further divided into more particle size ranges, and for oxyhalide solid electrolyte particles of different particle sizes, the parameters during ball milling (such as ball milling time, ball milling speed, etc.) can be adjusted to obtain oxyhalide solid electrolyte particles of different particle sizes. For example, the preparation raw materials and ball milling balls are placed in a ball milling jar, ball milling is performed at 200 rpm for 1 hour, and then ball milling is performed at 300 rpm for 1 hour to obtain an initial product, and the initial product is heat-treated to obtain an oxyhalide solid electrolyte; the oxyhalide solid electrolyte includes oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size.

[0082] In the embodiment of the present application, the following method may also be used to obtain oxyhalide solid electrolyte particles of different particle sizes, and the method may include:

[0083] Placing the prepared raw materials and ball milling balls in a ball milling jar, performing ball milling treatment at 200-500 rpm for 1-50 hours to obtain a first initial product, and heat treating the first initial product to obtain a first oxyhalide solid electrolyte; the heat treatment temperature is 80-400° C., and the time is 1-20 hours;

[0084] Placing the prepared raw materials and ball milling balls in a ball milling jar, performing ball milling treatment at 200-500 rpm for 1-50 hours to obtain a second initial product, and performing the heat treatment on the second initial product to obtain a second oxyhalide solid electrolyte;

[0085] The first oxyhalide solid electrolyte and the second oxyhalide solid electrolyte are mixed to obtain a target oxyhalide solid electrolyte; the target oxyhalide solid electrolyte includes oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size.

[0086] Furthermore, the above method may include:

[0087] Placing the prepared raw materials and ball milling balls in a ball milling jar, performing ball milling treatment at 200 rpm for 1 hour to obtain a first initial product, and heat treating the first initial product to obtain a first oxyhalide solid electrolyte; the heat treatment temperature is 80-400° C., and the time is 1-20 hours;

[0088] placing the prepared raw materials and ball milling balls in a ball milling jar, performing ball milling treatment at 300 rpm for 1 hour to obtain a second initial product, and performing the heat treatment on the second initial product to obtain a second oxyhalide solid electrolyte;

[0089] The first oxyhalide solid electrolyte and the second oxyhalide solid electrolyte are mixed to obtain a target oxyhalide solid electrolyte; the target oxyhalide solid electrolyte includes oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size.

[0090] In the embodiment of the present application, the ball milling process is not limited to a single time or two times, but can also be more times. Moreover, when performing multiple ball milling processes, the parameters of each ball milling process (such as ball milling time, ball milling speed, etc.) can be set to different parameters.

[0091] The embodiment of the present application can optimize the particle distribution of the oxyhalide solid electrolyte by ball milling to prepare an oxyhalide solid electrolyte material with higher ion conductivity, thereby optimizing the performance of the battery.

[0092] In the embodiment of the present application, three raw materials, LiOH, M2O5, and SOCl2 (M is Nb or Ta), are weighed respectively according to a certain molar ratio to obtain a preparation raw material, and then the preparation raw material and ball milling balls are placed in a ball milling jar for ball milling to obtain an initial product, and then the initial product is heat treated for 1-20 hours at a temperature of 80-400°C to finally obtain an oxyhalide solid electrolyte Li2O2-MCl5.

[0093] The preparation method provided in this embodiment can effectively reduce the cost of preparing Li2O2-MCl5 binary oxyhalide solid electrolyte. The present application adopts cheap M2O5 as M source and adds cheap SOCl2 as chlorinating agent to replace the original high-cost MCl5. Without changing the original general process flow and equipment and without reducing the conductivity of the product, the preparation cost of Li2O2-MCl5 binary oxyhalide solid electrolyte is greatly reduced, which is conducive to the large-scale application of the material in batteries; SOCl2 chlorinating agent as Cl source, its liquid properties also help lubricate the material during ball milling preparation, improve the uniformity of raw material mixing and reaction, improve the conductivity of the product, and also reduce the product residue on the surface of ball milling balls and ball milling beads, thereby effectively improving the yield.

[0094] The present application also provides an all-solid-state battery, which includes a composite positive electrode layer containing a positive electrode active material and an electrolyte, a composite negative electrode layer containing a negative electrode active material and an electrolyte, and an electrolyte layer as a separator between the positive and negative electrodes. At least one of the composite positive electrode layer and the separator layer contains Li2O2-MCl5, M=Nb, Ta, and preferably Li2O2-MCl5, M=Nb, Ta is selected on the composite positive electrode layer or the separator layer side close to the positive electrode layer.

[0095] In the embodiment of the present application, the positive electrode active material may include: rock salt layer type active material, such as LiCoO2, LiMnO2, LiNiO2, LiVO2 or Li 1+x Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2; spinel active materials, such as LiMn2O4 or Li(Ni 0.5 Mn 1.5 )O4; inverse spinel type active materials, such as LiNiVO4 or LiCoVO4; olivine type active materials, such as LiFePO4, LiMnPO4, LiCoPO4 or LiNiPO4; silicon-containing active materials, such as Li2FeSiO4 or Li2MnSiO; rock salt layer type active materials in which a portion of transition metals are replaced by heterogeneous metals, such as LiNi 0.8 Co (0.2-x) Al x O2 (0<x<0.2); spinel-type active materials in which a portion of transition metals are replaced by heterogeneous metals, such as Li 1+x Mn 2-x-y M y O4 (wherein M includes at least one of Al, Mg, Co, Fe, Ni, and Zn, and 0<x+y<2); and lithium titanate, such as Li4Ti5O 12 ; Sulfide positive electrode active materials may include: copper sulfide, iron sulfide, cobalt sulfide, nickel sulfide, etc.

[0096] In the embodiment of the present application, the negative electrode active material may include: a metal material, a carbon material, an oxide, a nitride, a tin compound or a silicon compound, etc. The metal material may be a single metal material, or may be an alloy. Examples of metal materials are lithium metal or lithium alloys. Examples of carbon materials are natural graphite, coke, graphitizable carbon, carbon fiber, spherical carbon, artificial graphite or amorphous carbon, etc. From the viewpoint of capacity density, suitable examples of negative electrode active materials are silicon, tin, silicon compounds or tin compounds.

[0097] In the embodiment of the present application, in addition to the Li2O2-MCl5 electrolyte, the solid electrolyte in the composite positive electrode layer, the composite negative electrode layer, and the electrolyte layer may include Li3YCl6, Li3InCl6, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is one of Ge, Zn and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, and In), Li 10 GeP2S 12 wait.

[0098] Embodiment 1:

[0099] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0100] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0101] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was carried out at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product. The mass ratio of the raw material to the ball milling balls was 1:20.

[0102] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4, whose XRD spectrum is as follows: Figure 6 shown.

[0103] Embodiment 2:

[0104] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0105] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 59.485 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 90.856 g of preparation raw materials; wherein x=0;

[0106] 90.856 g of the raw material and 1817 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0107] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0108] Embodiment 3:

[0109] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0110] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 71.382 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 102.753 g of preparation raw materials; wherein x=1;

[0111] 102.753 g of the raw material and 2055 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0112] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0113] Embodiment 4:

[0114] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0115] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 89.228 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 120.599 g of preparation raw materials; wherein x=2.5;

[0116] 120.599 g of the raw material and 2412 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0117] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0118] Embodiment 5:

[0119] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0120] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 118.97 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 150.341 g of preparation raw materials; wherein x=5;

[0121] 150.341 g of the raw material and 3007 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0122] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0123] Embodiment 6:

[0124] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0125] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 178.455 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 209.826 g of preparation raw materials; wherein x=10;

[0126] 209.826 g of the raw material and 4197 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0127] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0128] Embodiment 7:

[0129] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0130] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0131] 96.8 g of the raw material and 96.8 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0132] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0133] Embodiment 8:

[0134] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0135] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0136] 96.8 g of the raw material and 4840 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0137] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0138] Embodiment 9:

[0139] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0140] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0141] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 1 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0142] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0143] Embodiment 10:

[0144] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0145] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0146] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 50 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0147] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0148] Embodiment 11:

[0149] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0150] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0151] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 200 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0152] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0153] Embodiment 12:

[0154] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0155] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0156] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 500 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0157] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0158] Embodiment 13:

[0159] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0160] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0161] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0162] After no more gas can be discharged, the initial product is heat treated at 80℃ for 3h to obtain LiNbOCl4.

[0163] Embodiment 14:

[0164] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0165] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0166] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0167] After no more gas can be discharged, the initial product is heat treated at 400℃ for 3h to obtain LiNbOCl4.

[0168] Embodiment 15:

[0169] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0170] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0171] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0172] After no more gas can be discharged, the initial product is heat treated at 100℃-1h to obtain LiNbOCl4.

[0173] Embodiment 16:

[0174] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb. The specific preparation method includes:

[0175] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0176] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0177] After no more gas can be discharged, the initial product is heat treated at 100℃-20h to obtain LiNbOCl4.

[0178] Embodiment 17:

[0179] This embodiment provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Ta. The specific preparation method includes:

[0180] According to the molar ratio of 2:1:(5+x), 4.79 g, 44.189 g, and 65.434 g of LiOH, Ta2O5, and SOCl2 raw materials were weighed respectively to obtain 114.404 g of preparation raw materials; wherein x=0.5;

[0181] 114.404 g of the raw material and 2288 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was carried out at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product. The mass ratio of the raw material to the ball milling balls was 1:20.

[0182] After no more gas can be discharged, the initial product is heat treated at 300℃-15h to obtain LiTaOCl4, whose XRD spectrum is as follows: Figure 7 shown.

[0183] Comparative Example 1:

[0184] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0185] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 190.352 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 221.723 g of preparation raw materials; wherein x=11;

[0186] 221.723 g of the raw material and 4434 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0187] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0188] Comparative Example 2:

[0189] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0190] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0191] 96.8 g of the raw material and 48.4 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0192] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0193] Comparative Example 3:

[0194] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0195] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0196] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 0.5 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0197] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0198] Comparative Example 4:

[0199] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0200] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0201] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 100 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0202] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4.

[0203] Comparative Example 5:

[0204] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0205] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0206] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0207] After no more gas can be discharged, the initial product is heat treated at 70℃ for 3h to obtain LiNbOCl4.

[0208] Comparative Example 6:

[0209] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0210] According to the molar ratio of 2:1:(5+x), 4.79 g, 26.581 g, and 65.434 g of LiOH, Nb2O5, and SOCl2 raw materials were weighed respectively to obtain 96.8 g of preparation raw materials; wherein x=0.5;

[0211] 96.8 g of the raw material and 1936 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 20 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the by-products SO2 and HCl to obtain the initial product.

[0212] After no more gas can be discharged, the initial product is heat treated at 100℃-0.5h to obtain LiNbOCl4.

[0213] Comparative Example 7:

[0214] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Nb, and the specific preparation method includes:

[0215] According to the molar ratio of 2:1, 4.79 g and 27.017 g of LiOH and NbCl5 raw materials were weighed respectively to obtain 31.807 g of preparation raw materials;

[0216] 31.807 g of the raw material and 636 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was carried out at 400 rpm for 40 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the byproduct HCl to obtain the initial product. The mass ratio of the raw material to the ball milling balls was 1:20.

[0217] After no more gas can be discharged, the initial product is heat treated at 100℃ for 3h to obtain LiNbOCl4, whose XRD spectrum is as follows: Figure 8 shown.

[0218] Comparative Example 8:

[0219] This comparative example provides an oxyhalide solid electrolyte Li2O2-MCl5 and a preparation method thereof, wherein M=Ta, and the specific preparation method includes:

[0220] According to the molar ratio of 2:1, 4.79 g and 35.821 g of LiOH and TaCl5 raw materials were weighed respectively to obtain 40.611 g of preparation raw materials;

[0221] 40.611 g of the raw material and 812 g of zirconium dioxide ball milling balls were placed in a 2 L zirconium dioxide ball milling jar with a pressure relief valve, and the ball milling was performed at 400 rpm for 40 h. Then the ball milling was stopped, and the pressure relief valve was slowly opened to discharge the byproduct HCl to obtain the initial product. The mass ratio of the raw material to the ball milling balls was 1:20.

[0222] After no more gas can be discharged, the initial product is heat treated at 300℃-15h to obtain LiTaOCl4, whose XRD spectrum is as follows: Fig. 9 shown.

[0223] In the embodiments of the present application, the difference between Example 2 and Example 1 is that x=0, and the other conditions are the same as those of Example 1; the difference between Example 3 and Example 1 is that x=1, and the other conditions are the same as those of Example 1; the difference between Example 4 and Example 1 is that x=2.5, and the other conditions are the same as those of Example 1; the difference between Example 5 and Example 1 is that x=5, and the other conditions are the same as those of Example 1; the difference between Example 6 and Example 1 is that x=10, and the other conditions are the same as those of Example 1; the difference between Example 7 and Example 1 is that the mass of the zirconium dioxide ball milling ball is 96.8 g , other conditions are the same as those in Example 1; the difference between Example 8 and Example 1 is that the mass of the zirconium dioxide ball milling balls is 4840g, and other conditions are the same as those in Example 1; the difference between Example 9 and Example 1 is that the ball milling time is 1h, and other conditions are the same as those in Example 1; the difference between Example 10 and Example 1 is that the ball milling time is 50h, and other conditions are the same as those in Example 1; the difference between Example 11 and Example 1 is that the ball milling speed is 200rpm, and other conditions are the same as those in Example 1; the difference between Example 12 and Example 1 is that the ball milling speed is 500rpm, and its The other conditions are the same as those in Example 1; the difference between Example 13 and Example 1 is that the heat treatment temperature is 80°C, and the other conditions are the same as those in Example 1; the difference between Example 14 and Example 1 is that the heat treatment temperature is 400°C, and the other conditions are the same as those in Example 1; the difference between Example 15 and Example 1 is that the heat treatment time is 1h, and the other conditions are the same as those in Example 1; the difference between Example 16 and Example 1 is that the heat treatment time is 20h, and the other conditions are the same as those in Example 1; the difference between Comparative Example 1 and Example 1 is that x=11, and the other conditions are the same as those in Example 1 ; The difference between Comparative Example 2 and Example 1 is that the mass of the zirconium dioxide ball milling balls is 48.4 g, and the other conditions are the same as those in Example 1; the difference between Comparative Example 3 and Example 1 is that the ball milling time is 0.5 h, and the other conditions are the same as those in Example 1; the difference between Comparative Example 4 and Example 1 is that the ball milling speed is 100 rpm, and the other conditions are the same as those in Example 1; the difference between Comparative Example 5 and Example 1 is that the heat treatment temperature is 70°C, and the other conditions are the same as those in Example 1; the difference between Comparative Example 6 and Example 1 is that the heat treatment time is 0.5 h, and the other conditions are the same as those in Example 1.

[0224] In the examples of the present application, the products obtained from the above-mentioned examples and comparative examples were subjected to XRD test, conductivity test, yield calculation, cost calculation and all-solid-state battery test.

[0225] In the examples of the present application, the XRD test method is as follows: in an argon atmosphere, an X-ray diffraction device is used to measure the X-ray diffraction patterns of the solid electrolyte materials of some examples and comparative examples, using Cu-Kα rays as the X-ray source.

[0226] In the embodiments of the present application, the test method of the conductivity test is as follows: in an argon atmosphere, the powder of the solid electrolyte material of some embodiments and the comparative example is filled inside a pressurized mold. Inside the pressurized mold, a pressure of 500MPa is applied to the powder of the solid electrolyte material using upper and lower punches. Keeping the state of applying pressure unchanged, the upper part of the punch and the lower part of the punch are respectively connected to a constant potential instrument equipped with a frequency response analyzer, and the ionic conductivity of the solid electrolyte material is measured by the electrochemical impedance method. The real value of the impedance at the measuring point where the absolute value of the phase of the complex impedance is the smallest is regarded as the resistance value of the solid electrolyte material to ionic conduction.

[0227] In the examples of the present application, the yield is calculated by dividing the mass of the collected reaction product by the mass of the theoretical product calculated according to the chemical equation to calculate the yield of the product in percentage.

[0228] In the embodiment of the present application, the cost calculation method is: according to the maximum packaged commodity unit prices of LiOH (2.2 yuan / g), Ta2O5 (5.2 yuan / g), Nb2O5 (1.1 yuan / g), TaCl5 (31.5 yuan / g), NbCl5 (9.3 yuan / g), and SOCl2 (0.17 yuan / g) obtained from the official website of Aladdin Reagent https: / / www.aladdin-e.com / on August 24, 2024, calculate the raw material cost of the product.

[0229] In the embodiment of the present application, the test method of the all-solid-state battery test is: in an argon atmosphere, Li2O2-MCl5 solid electrolyte material and positive electrode active material, i.e., LiCoO2, are mixed in an agate mortar in a mass ratio of 30:70. These materials are mixed to obtain a positive electrode mixture. In an insulating cylinder, Li2O2-MCl5 (60 mg) and Li6PS5Cl solid electrolyte material (24 mg) are stacked in sequence to obtain a laminate. A pressure of 160 MPa is applied to the laminate to form a solid electrolyte layer. Then, on the Li2O2-MCl5 solid electrolyte layer, a positive electrode mixture (5 mg) is stacked to obtain a laminate. A pressure of 360 MPa is applied to the laminate to form a positive electrode. Then, a metal Li foil (thickness of 300 μm) is stacked on the solid electrolyte layer formed by Li6PS5Cl to obtain a laminate. A pressure of 5 MPa is applied to the laminate to form a negative electrode. A current collector made of stainless steel is placed on the positive electrode and the negative electrode, and a current collector lead is installed on the current collector. Finally, an insulating hoop is used to isolate the inside of the insulating tube from the external atmosphere, and the inside of the tube is sealed to obtain an all-solid-state battery. Fig.10 The battery was tested for 0.1-1C electrochemical performance in the voltage range of 2.5-4.2V.

[0230] Table 1. Physical property test results of different samples and all-solid-state battery cycle performance

[0231]

[0232] In the examples of the present application, the test data of the electrolytes obtained in the above examples and comparative examples are shown in Table 1. Fig.11 It can be obtained that with the increase of SOCl2 thionyl chloride molecules, the conductivity shows a trend of first increasing and then decreasing: the conductivity increases from 7.8mS / cm when SOCl2 is not excessive to 9.5mS / cm when SOCl2 is excessive by 10%, and then decreases to 1.7mS / cm when SOCl2 is excessive by 200%. There may be two reasons for this situation: on the one hand, SOCl2 thionyl chloride has a boiling point of 80°C and is volatile, and a slightly excessive amount of raw materials is conducive to the completeness of the reaction and the yield when discharging; on the other hand, when the liquid thionyl chloride is excessive, it is mixed with a gas and liquid mixture, and the solid material in the ball mill cannot effectively contact the ball mill, resulting in a decrease in the degree of reaction, and thus a decrease in conductivity.

[0233] In the embodiments of the present application, it can be obtained from Example 1, Examples 7-16 and Comparative Examples 1-6 that a suitable ball-to-material ratio is 1:20; a suitable ball milling time is 20 hours; a suitable ball milling speed is 400 rpm; the heat treatment temperature can be in the range of 80-400°C, preferably 100°C for M=Nb, and preferably 300°C for M=Ta; and a suitable heat treatment time is 3 hours.

[0234] In the examples of the present application, it can be obtained from Example 17 that the preparation method provided in the present application is also applicable to the LiTaOCl4 oxyhalide solid electrolyte system.

[0235] In the examples of the present application, it can be obtained from Example 1, Example 17, Comparative Example 7 and Comparative Example 8 that the conductivity of the product obtained by the low-cost preparation method of the oxyhalide solid electrolyte in the present application is very close to that of the product obtained by the traditional preparation method of the oxyhalide solid electrolyte using MCl5. In addition, Fig.12 As shown, by comparing their raw material costs, the preparation method of the present application has a cost as low as 22% of the TaCl5 preparation method when synthesizing LiTaOCl4; the preparation method of the present application has a cost as low as 19.5% of the NbCl5 preparation method when synthesizing LiNbOCl4. In terms of yield, the use of liquid raw materials also reduces the surface residue of the product on the ball milling balls and ball milling beads, thereby improving the yield. In addition, the rate performance of the all-solid-state battery is in direct proportion to the rate performance of the electrolyte.

[0236] It can be seen from the embodiments provided by the present application that the present application weighs LiOH, M2O5, and SOCl2 respectively according to the molar ratio of 2:1:(5+x) to obtain a preparation raw material; wherein, the range of x is 0-10, and M is Nb or Ta; the preparation raw material and ball milling balls are placed in a ball milling jar for 1-50 hours of ball milling to obtain an initial product; the ball milling speed corresponding to the ball milling treatment is 200-500rpm; the initial product is heat-treated at 80-400°C to obtain an oxyhalide solid electrolyte Li2O2-MCl5; the heat treatment time is 1-20h; the oxyhalide solid electrolyte Li2O2-MCl5 is formed by the accumulation of multiple spherical oxyhalide solid electrolyte particles, and the particle size range of the oxyhalide solid electrolyte particles is 0.5-3μm. The present application adopts cheap M2O5 as the M source, and adds cheap SOCl2 as the chlorinating agent to replace the original high-cost MCl5. Without changing the original general process flow and equipment and without reducing the conductivity of the product, the preparation cost of the Li2O2-MCl5 binary oxyhalide solid electrolyte is greatly reduced, which is conducive to the large-scale application of the material in batteries; the liquid property of the SOCl2 chlorinating agent as a Cl source also helps the lubrication of the material during ball milling preparation, improves the uniformity of raw material mixing and reaction, improves the conductivity of the product, and also reduces the product residue on the surface of the ball milling balls and ball milling beads, thereby effectively improving the yield.

[0237] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing an oxyhalide solid electrolyte, characterized in that: The method comprises: LiOH, M2O5, and SOCl2 are weighed respectively according to a molar ratio of 2:1:(5+x) to obtain a raw material for preparation; wherein x ranges from 0 to 10, and M is Nb or Ta; The raw materials and the ball milling balls are placed in a ball milling jar for 1-50 hours to obtain an initial product; the ball milling speed corresponding to the ball milling treatment is 200-500 rpm; The initial product is heat-treated at 80-400° C. to obtain the oxyhalide solid electrolyte Li2O2-MCl5; the heat treatment time is 1-20 hours; the oxyhalide solid electrolyte Li2O2-MCl5 is formed by the accumulation of a plurality of spherical oxyhalide solid electrolyte particles, and the particle size range of the oxyhalide solid electrolyte particles is 0.5-3 μm.

2. The method according to claim 1, characterized in that The preparation raw materials and ball milling balls are placed in a ball milling jar for 1-50 hours to obtain an initial product, including: Placing the raw material and the ball milling balls in the ball milling jar for ball milling to obtain a mixture of the initial product, the ball milling balls and by-products; the mass ratio of the raw material to the ball milling balls is 1:(1-50); After the ball milling treatment is completed, the pressure relief valve of the ball milling tank is opened to separate the by-products to obtain a mixture of the initial product and the ball milling balls; The initial product and the mixture of the ball milling balls are separated by using a sieve to obtain the initial product; the specification of the sieve is 20-50 meshes.

3. The method according to claim 1, characterized in that The initial product is heat treated at 80-400° C. to obtain the oxyhalide solid electrolyte Li2O2-MCl5, comprising: Heat treating the initial product at 80-400° C. for 0.5-1 h to obtain an intermediate product; The intermediate product is further subjected to heat treatment at 80-400° C. for 0.5-19 h to obtain the oxyhalide solid electrolyte Li2O2-MCl5.

4. The method according to claim 2, characterized in that: The by-products include SO2 gas and HCl gas.

5. The method according to claim 1, characterized in that In the X-ray diffraction test, the characteristic peaks of the oxyhalide solid electrolyte Li2O2-MCl5 are located at 2θ=13.5°, 2θ=24-25° and 2θ=31-32°.

6. The method according to claim 1, characterized in that The yield of the oxyhalide solid electrolyte Li2O2-MCl5 is greater than or equal to 94%; the yield of the oxyhalide solid electrolyte Li2O2-MCl5 is positively correlated with the feed amount of SOCl2.

7. The method according to claim 1, characterized in that The ionic conductivity of the oxyhalide solid electrolyte Li2O2-MCl5 is 1.7-9.5 mS / cm.

8. The method according to claim 1, characterized in that The oxyhalide solid electrolyte particles include oxyhalide solid electrolyte particles of a first particle size and oxyhalide solid electrolyte particles of a second particle size, the number of oxyhalide solid electrolyte particles of the first particle size is greater than that of oxyhalide solid electrolyte particles of the second particle size; the first particle size range is 0.5-2μm, and the second particle size range is 2.1-3μm.

9. An oxyhalide solid electrolyte, characterized in that: The oxyhalide solid electrolyte is prepared by the preparation method according to any one of claims 1 to 8.

10. An all-solid-state battery, characterized in that: The all-solid-state battery comprises the oxyhalide solid electrolyte as claimed in claim 9.

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