Anti-perovskite solid electrolyte material, preparation method thereof, solid electrolyte sheet, and all-solid-state battery

Abstract

This application relates to the field of all-solid-state battery technology, specifically to an anti-perovskite solid electrolyte material and its preparation method, a solid electrolyte sheet, and an all-solid-state battery. The anti-perovskite solid electrolyte material includes a cubic phase (Li). 2‑y M y / m )B(A 1‑2x S x ), where M is a metal cation with valence state m, and B includes OH. ‑ SH ‑ 、SeH ‑ F ‑ and H ‑ At least one of them, A includes F ‑ Cl ‑ ,Br ‑ and I ‑ At least one of the following, 0 < x ≤ 0.3, 0 ≤ y < 2. The anti-perovskite solid electrolyte material provided in this application can form a cubic phase crystal with a stable structure; it is also beneficial to increase ion transport vacancies, reduce ion transfer activation energy, and thus improve the ionic conductivity of the anti-perovskite solid electrolyte material, showing good application prospects.

Description

Technical Field

[0001] This application relates to the field of all-solid-state battery technology, and more specifically, to an anti-perovskite solid electrolyte material and its preparation method, a solid electrolyte sheet, and an all-solid-state battery. Background Technology

[0002] With the development of technology, rechargeable batteries are widely used in portable electronic devices, electric vehicles, and charging stations. All-solid-state batteries use solid electrolytes instead of traditional liquid electrolytes, which can effectively stabilize the electrolyte interface, improve the safety of rechargeable batteries, and increase their energy density. Among them, anti-perovskite solid electrolytes have advantages such as low activation barrier, low electronic conductivity, wide electrochemical window, good chemical stability to lithium metal, light weight, and environmental friendliness, showing promising application prospects.

[0003] However, existing anti-perovskite solid electrolytes generally suffer from low ionic conductivity, which cannot adequately meet the requirements of secondary batteries and greatly limits their application. Summary of the Invention

[0004] The purpose of this application is to provide an anti-perovskite solid electrolyte material and its preparation method, a solid electrolyte sheet and an all-solid-state battery, which aims to improve the technical problem of low ionic conductivity of existing anti-perovskite solid electrolytes.

[0005] Firstly, this application provides an anti-perovskite solid electrolyte material, including a cubic phase (Li). 2-y M y / m )B(A 1-2x S x ), where M is a cation with valence state m, and B includes OH. - SH - 、SeH - F - and H - At least one of them, A includes F - Cl - ,Br - and I - At least one of the following, 0 < x ≤ 0.3, 0 ≤ y < 2.

[0006] The anti-perovskite solid electrolyte material provided in this application can form a cubic phase crystal with a stable structure, which is also beneficial for increasing ion transport vacancies, reducing ion transfer activation energy, and thus improving the ionic conductivity of the anti-perovskite solid electrolyte material.

[0007] In one possible implementation, M includes Na. + K + 、Rb + Mg2+ Ca 2+ 、Sr 2+ Zn 2+ La 3+ Al 3+ Ga 3+ Si 4+ 、Ge 4+ and Sn 4+ At least one of them.

[0008] Alternatively, y = 0, and B is OH. - A is Br - .

[0009] In one possible implementation, the solid electrolyte material comprises a cubic phase Li₂OHBr. 0.8 S 0.1 cubic phase Li2OHBr 0.6 S 0.2 and cubic phase Li2OHBr 0.4 S 0.3 At least one of them.

[0010] The aforementioned substances have a large number of ion transport vacancies, which can effectively reduce the ion transfer activation energy, thereby improving the ionic conductivity of anti-perovskite solid electrolyte materials.

[0011] Secondly, this application provides a method for preparing an anti-perovskite solid electrolyte material as described in the first aspect above, comprising following the general formula (Li 2-y M y / m )B(A 1-2x S x After mixing the raw materials, press them at 0.1-10 GPa and 300-1000℃ for at least 10 minutes.

[0012] According to the general formula (Li 2-y M y / m )B(A 1-2x S x The raw materials are mixed and then pressed for synthesis. The pressing synthesis conditions of 0.1-10 GPa, 300-1000℃ and not less than 10 min are conducive to the rapid preparation of cubic anti-perovskite solid electrolyte materials with good crystallinity and high purity. Moreover, the prepared cubic anti-perovskite solid electrolyte materials can increase ion transport vacancies and reduce ion transfer activation energy, which is beneficial to improving the ionic conductivity of anti-perovskite solid electrolyte materials.

[0013] In one possible implementation, when y is 0 and A is Br - And B is OH - The raw materials include LiOH, LiBr and Li2S.

[0014] In one possible implementation, the compression synthesis pressure is 1-5 GPa, the compression synthesis temperature is 400-600℃, and the compression synthesis time is 20-40 min.

[0015] The above-mentioned pressing synthesis conditions can ensure that the obtained anti-perovskite solid electrolyte material has good crystallinity and high purity, while achieving rapid preparation of cubic anti-perovskite solid electrolyte material.

[0016] Optionally, the compression synthesis pressure is 3 GPa, the compression synthesis temperature is 500℃, and the compression synthesis time is 30 min.

[0017] In one possible implementation, the step of mixing the raw materials includes: ball milling the raw materials at a speed of 200-600 rpm for 2-6 hours.

[0018] Under the above-mentioned ball milling conditions, the raw materials can be thoroughly ground, improving the mixing uniformity of the raw materials. This is beneficial to improving the utilization rate of raw materials in the subsequent pressing synthesis process, reducing the generation of by-products, and improving the purity and ionic conductivity of cubic reverse perovskite solid electrolyte materials. It also helps to increase the reaction rate of pressing synthesis.

[0019] In one possible implementation, the step of mixing the raw materials and the step of pressing and synthesizing the raw materials further include pre-pressing the mixed raw materials at 200-100 MPa for 1-5 minutes.

[0020] Before pressing synthesis, the raw material mixture is pre-pressed at 20-100MPa for 1-5 minutes. This makes the raw materials more tightly bonded, which is beneficial to improve the collision effect between atoms during the subsequent pressing synthesis process. This, in turn, helps to improve the crystallinity of the anti-perovskite solid electrolyte material, increase the ion transport vacancies, and improve the ionic conductivity of the anti-perovskite solid electrolyte material.

[0021] Thirdly, this application provides a solid electrolyte sheet, comprising the anti-perovskite solid electrolyte material provided in the first aspect above, or the anti-perovskite solid electrolyte material prepared by the preparation method of the anti-perovskite solid electrolyte material provided in the second aspect above.

[0022] The solid electrolyte sheet provided in this application has high ionic conductivity and has good application prospects.

[0023] Fourthly, this application provides an all-solid-state battery, including the solid electrolyte sheet provided in the third aspect above.

[0024] The all-solid-state battery provided in this application has high ionic conductivity. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The SEM images of the anti-perovskite solid electrolyte material provided in Embodiment 1 of this application are shown at different magnifications.

[0027] Figure 2 The XRD comparison diagrams of the anti-perovskite solid electrolyte materials provided in Examples 1-3 and Comparative Examples 1-2 of this application are shown.

[0028] Figure 3 The diagram shows a comparison of the ionic conductivity of the anti-perovskite solid electrolyte materials provided in Examples 1-3 and Comparative Examples 1-2 of this application at different temperatures. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] This application provides an anti-perovskite solid electrolyte material, including a cubic phase (Li). 2-y M y / m )B(A 1-2x S x ), where M is a cation with valence state m, and B includes OH. - SH - 、SeH - F - and H - At least one of them, A includes F - Cl - ,Br - and I - At least one of the following, 0 < x ≤ 0.3, 0 ≤ y < 2.

[0031] This application enables the anti-perovskite solid electrolyte material to form a cubic phase crystal with a stable structure by selecting atoms and adjusting the atomic ratio. This also helps to increase ion transport vacancies, reduce ion transfer activation energy, and thus improve the ionic conductivity of the anti-perovskite solid electrolyte material.

[0032] It should be noted that the general formula of the anti-perovskite solid electrolyte material in this application is (Li 2-y M y / m )B(A 1-2x S x In this context, Li represents metallic lithium, and S represents sulfur.

[0033] For example, x can be 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3, etc.; y can be 0, 0.5, 1, 1.5, or 1.95, etc.

[0034] M includes Na + K + 、Rb + Mg 2+ Ca 2+ 、Sr 2+ Zn 2+ La 3+ Al 3+ Ga 3+ Si 4+ 、Ge 4+ and Sn 4+ At least one of them.

[0035] In the embodiments of this application, y = 0, and B is OH. - A is Br - At this point, the general formula for anti-perovskite solid electrolyte materials is Li₂OH(Br₂)₃. 1-2x S x Since the Li-S bond is much weaker than the Li-Br bond, and in the Br... - By creating vacancies at the positions, the activation energy for lithium-ion diffusion is greatly reduced, thereby improving the lithium-ion conductivity of the anti-perovskite solid electrolyte material.

[0036] As an example, the solid electrolyte material includes the cubic phase Li2OHBr. 0.8 S 0.1 cubic phase Li2OHBr 0.6 S 0.2 and cubic phase Li2OHBr 0.4 S 0.3At least one of the above substances has a large number of ion transport vacancies, which can effectively reduce the ion transfer activation energy and thus help improve the ionic conductivity of anti-perovskite solid electrolyte materials.

[0037] This application also provides a method for preparing an anti-perovskite solid electrolyte material, comprising:

[0038] S10, Prepare raw materials.

[0039] According to the general formula (Li 2-y M y / m )B(A 1-2x S x Prepare the raw materials.

[0040] In the embodiments of this application, y = 0, and B is OH. - A is Br - In this case, LiOH, LiBr, and Li₂S are selected as the raw materials for preparing the anti-perovskite solid electrolyte material. The preparation principle of the anti-perovskite solid electrolyte material is as follows: LiOH + (1-2x)LiBr + xLi₂S → Li₂OH(Br) 1-2x S x) (0 < x ≤ 0.3).

[0041] In the raw materials, the molar ratio of LiOH, LiBr, and Li₂S is 1:(1-2x):x; where 0 < x ≤ 0.3. By adjusting the atomic ratio of Br and S, when 0 < x ≤ 0.3, it is beneficial to subsequently prepare a cubic phase anti-perovskite solid electrolyte material with a stable structure. x This also helps to increase ion transport vacancies in solid electrolytes, which helps to reduce the ion transfer activation energy and thus improve the ionic conductivity of anti-perovskite solid electrolyte materials.

[0042] For example, x can be 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3, etc.

[0043] It should be noted that in other embodiments of this application, when y = 0, B can also SH. - 、SeH - F - and H - At least one of them, A may also be selected from F - Cl - ,Br - and I - At least one of the following; y can also be non-zero, such as 0.5, 1, 1.5 or 1.95, etc.

[0044] S20, mixed raw materials.

[0045] The steps of mixing raw materials include ball milling the raw materials.

[0046] Furthermore, mixing the raw materials under vacuum conditions is beneficial for further improving the crystallinity and purity of the anti-perovskite solid electrolyte material.

[0047] Furthermore, the aforementioned sealed conditions include sealed containers that are free of water or contain only trace amounts of water, which helps to prevent the raw materials from absorbing moisture and affecting the subsequent pressing and synthesis reactions as well as the synthesis effect.

[0048] In the embodiments of this application, the ball milling speed is 200-600 rpm, and the ball milling time is 2-6 hours. Under the above ball milling conditions, the raw materials can be thoroughly ground, improving the mixing uniformity of the raw materials, which in turn helps to improve the utilization rate of raw materials in the subsequent pressing synthesis process, reduce the generation of by-products, and improve the purity and ionic conductivity of the cubic reverse perovskite solid electrolyte material; it also helps to improve the reaction rate of pressing synthesis.

[0049] For example, the ball milling speed can be 200 rpm, 300 rpm, 400 rpm, 500 rpm or 600 rpm, etc.; the ball milling time can be 2h, 3h, 4h, 5h or 6h, etc.

[0050] S30, pre-compressed raw material.

[0051] The pre-compression step involves pre-compressing the mixed raw materials at 20-100 MPa for 1-5 minutes, which makes the bonding between the raw materials tighter, which is beneficial to improve the collision effect between atoms during the subsequent compression synthesis process. This, in turn, helps to improve the crystallinity of the anti-perovskite solid electrolyte material, increase the ion transport vacancies, and improve the ionic conductivity of the anti-perovskite solid electrolyte material.

[0052] For example, the pre-compression pressure can be 20MPa, 40MPa, 60MPa, 90MPa or 100MPa, etc.; the pre-compression time can be 1min, 1.5min, 2min, 3min, 4min or 5min, etc.

[0053] S40 is used to press and synthesize raw materials to obtain anti-perovskite solid electrolyte materials.

[0054] The pressing synthesis step involves pressing the raw materials at 0.1-10 GPa and 300-1000 °C for at least 10 min. These pressing synthesis conditions are beneficial for increasing the crystal growth rate, enabling the rapid preparation of cubic anti-perovskite solid electrolyte materials with good crystallinity and high purity. Furthermore, the obtained cubic anti-perovskite solid electrolyte material can increase ion transport vacancies and reduce ion transfer activation energy, which is beneficial for improving the ionic conductivity of the anti-perovskite solid electrolyte material. The pressing synthesis process described in this application is simple and holds promise for large-scale production.

[0055] Furthermore, the compression synthesis time is 10-120 min.

[0056] For example, the pressure for compression synthesis can be 0.1 GPa, 0.5 GPa, 1 GPa, 3 GPa, 5 GPa, or 10 GPa, etc.; the temperature for compression synthesis can be 300℃, 400℃, 500℃, 700℃, or 1000℃, etc.; and the time for compression synthesis can be 10 min, 30 min, 60 min, 90 min, or 120 min, etc.

[0057] Furthermore, the pressing synthesis pressure is 1-5 GPa, the pressing synthesis temperature is 400-600℃, and the pressing synthesis time is 20-40 min. This can ensure that the obtained anti-perovskite solid electrolyte material has good crystallinity and high purity while achieving rapid preparation of cubic anti-perovskite solid electrolyte material.

[0058] Furthermore, the pressing synthesis pressure is 3 GPa, the pressing synthesis temperature is 500℃, and the pressing synthesis time is 30 min, which can further improve the crystal growth rate, so as to quickly prepare cubic anti-perovskite solid electrolyte materials with good crystallinity and high purity; and further increase the ion transport vacancies of the anti-perovskite solid electrolyte material and reduce the ion transfer activation energy, which is beneficial to improving the ionic conductivity of the anti-perovskite solid electrolyte material.

[0059] In the embodiments of this application, after compression synthesis, the product after compression synthesis is further subjected to surface grinding to remove impurity powder remaining on the surface of the product due to the compression synthesis process, thereby improving the purity of the anti-perovskite solid electrolyte material.

[0060] As an example, the pressing and bonding apparatus can be selected from any one of a two-sided press, a four-sided press, and a hinged six-sided press.

[0061] This application also provides a solid electrolyte sheet, comprising the anti-perovskite solid electrolyte material provided above or an anti-perovskite solid electrolyte material prepared by the preparation method of the anti-perovskite solid electrolyte material provided above.

[0062] The solid electrolyte sheet provided in this application has high ionic conductivity and has good application prospects.

[0063] This application provides an all-solid-state battery, including the solid electrolyte sheet provided above.

[0064] The all-solid-state battery provided in this application has high ionic conductivity.

[0065] The following detailed description of the features and properties of the anti-perovskite solid electrolyte material and its preparation method, in conjunction with embodiments, further illustrates these features.

[0066] Example 1

[0067] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.4 S 0.3 It is prepared using the following steps:

[0068] Using LiOH, LiBr, and Li₂S as raw materials, the raw materials were weighed according to a molar ratio of 1:0.4:0.3. The raw materials were placed in a vacuum ball mill jar for thorough ball milling at 400 rpm for 6 hours. The ball-milled powder was pre-pressed into cylindrical shapes at a pressure of 100 MPa for 2 minutes. The pre-pressed cylindrical blanks were then pressed at 3 GPa and 500℃ for 30 minutes. The surface of the pressed product was then ground to obtain the anti-perovskite solid electrolyte material Li₂OHBr. 0.4 S 0.3 .

[0069] Example 2

[0070] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.6 S 0.2 The preparation steps in this embodiment are basically the same as those in Example 1, except that the raw materials are weighed according to the molar ratio of LiOH, LiBr and Li2S of 1:0.6:0.2.

[0071] Example 3

[0072] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.8 S 0.1 The preparation steps in this embodiment are basically the same as those in Example 1, except that the raw materials are weighed according to the molar ratio of LiOH, LiBr and Li2S of 1:0.8:0.1.

[0073] Example 4

[0074] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.4 S 0.3 The preparation steps in this embodiment are basically the same as those in Example 1, except that the pressure for pressing synthesis is 1 GPa and the temperature for pressing synthesis is 600℃.

[0075] Example 5

[0076] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.4 S 0.3 The preparation steps in this embodiment are basically the same as those in Example 1, except that the compression synthesis time is 1 hour.

[0077] Example 6

[0078] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.4 S 0.3 The preparation steps in this embodiment are basically the same as those in Example 1, except that the ball milling speed is 200 rpm and the ball milling time is 6 hours.

[0079] Example 7

[0080] This embodiment provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.4 S 0.3 The preparation steps in this embodiment are basically the same as those in Example 1, except that the pre-compression pressure is 20 MPa and the pre-compression time is 2 min.

[0081] Comparative Example 1

[0082] This comparative example provides an anti-perovskite solid electrolyte material, Li2OHBr. The preparation steps of this comparative example are basically the same as those of Example 1, except that LiOH and LiBr are used as raw materials, and the raw materials are weighed according to a molar ratio of 1:1 between LiOH and LiBr.

[0083] Comparative Example 2

[0084] This comparative example provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.3 S 0.35 The preparation steps of this comparative example are basically the same as those of Example 1, except that the raw materials are weighed according to the molar ratio of LiOH, LiBr and Li2S of 1:0.3:0.35.

[0085] Comparative Example 3

[0086] This comparative example provides an anti-perovskite solid electrolyte material, Li2OHBr. 0.4 S 0.3The preparation steps of this comparative example are basically the same as those of Example 1, except that the pressure of the compression synthesis is 15 GPa and the temperature of the compression synthesis is 1200℃.

[0087] Experimental Example 1

[0088] The anti-perovskite solid electrolyte material provided in Example 1 was characterized by SEM, and the characterization results are as follows: Figure 1 As shown; where Figure 1 The magnification of part A is 1500x. Figure 1 The magnification of part B is 2000x. Figure 1 The magnification of part C is 3000x. Figure 1 The magnification of part D is 10000x.

[0089] from Figure 1 It can be seen that the anti-perovskite solid electrolyte material Li2OHBr improved in Example 1 0.4 S 0.3 It has good crystallinity.

[0090] Experiment Example 2

[0091] The anti-perovskite solid electrolyte materials provided in Examples 1-3 and Comparative Examples 1-2 were characterized by XRD and their ionic conductivity was tested at different temperatures. The XRD characterization results are as follows: Figure 2 As shown, the ionic conductivity results are as follows: Figure 3 As shown.

[0092] from Figure 2 It can be seen that the anti-perovskite solid electrolyte materials provided in Examples 1-3 have a cubic phase crystal structure, while the anti-perovskite solid electrolyte materials provided in Comparative Examples 1-2 have cubic and tetragonal phase crystal structures, respectively; from Figure 3 It can be seen that the ionic conductivity of the anti-perovskite solid electrolyte materials provided in Examples 1-3 is significantly higher than that of the anti-perovskite solid electrolyte materials provided in Comparative Examples 1-2. This indicates that the anti-perovskite solid electrolyte materials contain both halogen elements and sulfur elements. When the ratio of halogen elements to sulfur elements is (1-2x):x and 0 < x ≤ 0.3, the prepared anti-perovskite solid electrolyte materials can form a cubic phase crystal with a stable structure, which is also beneficial to improving the ionic conductivity of the anti-perovskite solid electrolyte materials.

[0093] Experimental Example 3

[0094] The ionic conductivity of the anti-perovskite solid electrolyte materials provided in Examples 1, 4-7 and Comparative Example 3 was tested at 25°C, and the results are shown in Table 1.

[0095] Table 1

[0096]

[0097] As can be seen from Table 1, a comparison between Examples 4-7 and Example 1 shows that the temperature, pressure, and time of pressing synthesis, the rotation speed and time of ball milling, and the pressure and time of pre-pressing all affect the ionic conductivity of the anti-perovskite solid electrolyte material. Furthermore, a comparison between Example 1 and Comparative Example 3 shows that Comparative Example 3 could not be effectively synthesized under pressing synthesis conditions of 15 GPa and 1200 °C, resulting in poor ionic conductivity of the anti-perovskite solid electrolyte material of Comparative Example 3. This indicates that the pressing synthesis conditions specified in this application can improve the ionic conductivity of the anti-perovskite solid electrolyte material.

[0098] In summary, the anti-perovskite solid electrolyte material provided in this application can form a cubic phase crystal with a stable structure; it also helps to increase ion transport vacancies, reduce ion transfer activation energy, and thus improve the ionic conductivity of the anti-perovskite solid electrolyte material, showing good application prospects.

[0099] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing an anti-perovskite solid electrolyte material, characterized in that, include: After mixing the raw materials, press them at 1-5 GPa and 400-600℃ for at least 10 minutes to synthesize them. The raw materials are LiOH, Li2S and LiBr, and the molar ratio of LiOH:Li2S:LiBr is 1:x:(1-2x), where x is 0.1, 0.2 or 0.

3. The step of mixing the raw materials includes: ball milling the raw materials at a speed of 200-600 rpm for 2-6 hours; The anti-perovskite solid electrolyte material is cubic Li₂OHBr₂. 0.8 S 0.1 cubic phase Li2OHBr 0.6 S 0.2 or cubic phase Li2OHBr 0.4 S 0.3 .

2. The method for preparing the anti-perovskite solid electrolyte material according to claim 1, characterized in that, The compression synthesis time is 20-40 minutes.

3. The method for preparing the anti-perovskite solid electrolyte material according to claim 2, characterized in that, The pressing and synthesis pressure is 3 GPa, the pressing and synthesis temperature is 500℃, and the pressing and synthesis time is 30 min.

4. The method for preparing the anti-perovskite solid electrolyte material according to claim 1, characterized in that, Between the step of mixing the raw materials and the step of pressing and synthesizing, the raw material mixture is further pre-pressed at 20-100 MPa for 1-5 minutes.

5. An anti-perovskite solid electrolyte material prepared by the preparation method according to any one of claims 1 to 4.

6. A solid electrolyte sheet, characterized in that, Including the anti-perovskite solid electrolyte material as described in claim 5.

7. An all-solid-state battery, characterized in that, Includes the solid electrolyte sheet as described in claim 6.

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