Preparation method of Li3OCl solid electrolyte
By mixing LiCl and Li2O with ether organic solvents, Li3OCl solid electrolyte is prepared, which solves the problems of long synthesis cycle and low yield in the prior art, and achieves high-efficiency and low energy consumption large-scale production.
Patent Information
- Application Number
- CN202411653147.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-03-25
AI Technical Summary
The existing Li3OCl solid electrolyte is prepared by solid-phase sintering method, with a long synthesis cycle and low yield, making it difficult to meet the needs of commercial large-scale production.
The raw materials LiCl and Li2O were mixed, and the ether-based organic solvent was added for reaction, and then filtered and dried to obtain Li3OCl solid electrolyte. This method avoids high temperature sintering of solid phase, reduces energy consumption, and improves yield and purity.
The preparation of Li3OCl solid electrolyte with high yield (more than 94%) has been achieved, which reduces energy consumption, improves the purity and electrochemical stability window of the product, and is suitable for commercial large-scale production.
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Figure CN119683657A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for preparing a Li3OCl solid electrolyte. Background Art
[0002] All-solid-state lithium batteries have attracted widespread attention due to their high theoretical energy density and high safety. Among them, inorganic solid electrolytes (ISSEs) are expected to be used in all-solid-state lithium batteries, but the synthesis of most inorganic solid electrolytes requires high sintering temperatures and cannot meet commercial needs. Therefore, the development of inorganic solid electrolytes with high ionic conductivity and easy preparation is considered to be the main challenge in the development of all-solid-state lithium batteries.
[0003] Li3OCl solid electrolyte has high ionic conductivity and good compatibility with oxide cathodes, so it can be used in all-solid-state lithium batteries. Currently, Li3OCl solid electrolytes are mostly prepared by solid-phase sintering, which has a long synthesis cycle, low yield, high energy consumption, and is not suitable for commercial large-scale production. Summary of the invention
[0004] In view of the above analysis, the present invention aims to provide a method for preparing a Li3OCl solid electrolyte, so as to solve the technical problems that the existing Li3OCl solid electrolyte is prepared by a solid phase sintering method, has a long synthesis cycle and low yield.
[0005] The purpose of the present invention is mainly achieved through the following technical solutions:
[0006] The present invention provides a method for preparing a Li3OCl solid electrolyte, the preparation method comprising:
[0007] The raw materials LiCl and Li2O are mixed, an ether organic solvent is added to react, and then filtered and dried to obtain a Li3OCl solid electrolyte.
[0008] Furthermore, the ether organic solvent includes one or more of xylyl ether, p-tert-butylanisole and biphenyl ether.
[0009] Furthermore, the mass ratio of the ether organic solvent to LiCl is 3 to 5:1.
[0010] Furthermore, the reaction temperature is 190-220°C.
[0011] Furthermore, the reaction time is 20 to 27 hours.
[0012] Furthermore, stirring is performed during the reaction.
[0013] Further, the drying is carried out in a vacuum tube furnace.
[0014] Furthermore, the drying temperature is 200-240°C.
[0015] Furthermore, the drying time is 2 to 5 hours.
[0016] Furthermore, the preparation method further comprises: grinding the dried Li3OCl.
[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:
[0018] (1) The preparation method of the present invention dissolves the raw materials LiCl and Li2O in an ether organic solvent, so that the raw materials are fully in contact, the reaction rate is accelerated to generate Li3OCl solid electrolyte, and the ether solvent does not participate in the reaction, which can improve the purity of the product; the method is easy to operate and easy to commercialize and mass produce.
[0019] (2) The preparation method of the present invention avoids solid-phase high-temperature sintering and can reduce energy consumption; the yield of the present invention is high, for example, the yield can reach more than 94%, for example, 94.8% to 96%.
[0020] (3) The Li3OCl obtained by the preparation method of the present invention is high in purity and free of impurities, with a purity close to 100%. The electrochemical stability window of the obtained Li3OCl is wide, reaching -1 to 9V, which can meet the commercial application requirements of high-voltage all-solid-state batteries.
[0021] (4) The ether solvent of the present invention does not participate in the reaction and can be recycled, further reducing the synthesis cost.
[0022] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.
[0024] Figure 1 is a flow chart of the preparation method of Example 1 of the present invention;
[0025] Figure 2 The XRD diagrams of the products of Example 1 and Comparative Examples 1 to 5 are shown;
[0026] Figure 3CV curves of Li3OCl solid electrolytes prepared in Examples 1 to 3 and Comparative Example 1;
[0027] Figure 4 is a flow chart of the preparation method of Comparative Example 1;
[0028] Figure 5 Flow chart of the preparation method of Comparative Example 2. DETAILED DESCRIPTION
[0029] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.
[0030] The present invention provides a method for preparing a Li3OCl solid electrolyte, comprising:
[0031] The raw materials LiCl and Li2O are mixed, an ether organic solvent is added to react, and then filtered and dried to obtain a Li3OCl solid electrolyte.
[0032] Specifically, in order to make the raw materials LiCl and Li2O react completely and avoid raw material residue, the molar ratio of LiCl and Li2O is controlled to be 1:1.
[0033] Specifically, the ether organic solvent may include one or more of xylyl ether, p-tert-butylanisole and biphenyl ether.
[0034] Considering that when the mass of the ether organic solvent is too much, the concentration of the raw material in the solvent is low and the reaction is slow; when it is too little, the concentration of the raw material in the solvent is high, the molecular motion slows down, and the reaction rate slows down. Therefore, the mass ratio of the ether organic solvent to LiCl is controlled to be 3 to 5:1, such as 3:1, 4:1, 5:1.
[0035] Specifically, considering that the temperature of adding ether organic solvent for reaction cannot reach the temperature required for the synthesis reaction when it is too low, and side reactions occur when it is too high, producing ether compound impurities; therefore, the reaction temperature is controlled to be 190-220°C, for example, 190°C, 200°C, 210°C.
[0036] Specifically, considering that if the time of adding the ether organic solvent to react is too short, the raw materials will not react completely and the raw materials will remain; if it is too long, the synthesized Li3OCl antiperovskite structure will be unstable and the structure will collapse. Therefore, the reaction time is controlled to be 20 to 27 hours, such as 22 hours, 24 hours, and 26 hours.
[0037] Specifically, the route of the above reaction is:
[0038]
[0039] Specifically, considering that during the reaction, the generation of Li3OCl will lead to the deposition of Li3OCl, which will reduce the reaction rate, therefore, stirring is required during the reaction.
[0040] For example, during the reaction, stirring is performed once when the reaction time is about halfway through.
[0041] Specifically, the above reaction needs to be carried out in a sealed reactor to avoid contamination of the synthetic product by external moisture.
[0042] Specifically, in order to prevent residual organic solvent on the surface of Li3OCl, the drying can be vacuum dried in a vacuum tube furnace. The vacuum environment is conducive to drying the organic solvent on the surface of Li3OCl at a lower temperature.
[0043] Specifically, when the drying temperature is too low, it is difficult to remove the organic solvent on the surface, and when it is too high, the organic solvent on the surface undergoes a side reaction to produce ether compounds; therefore, the drying temperature is controlled to be 200-240°C, for example, 210°C, 220°C, 230°C.
[0044] Specifically, if the drying time is too long, the structure of Li3OCl is easily destroyed, resulting in the collapse of the antiperovskite structure, and if the drying time is too short, it is difficult to completely dry the surface organic solvent; therefore, the drying time is controlled to be 2 to 5 hours, for example, 3 hours or 4 hours.
[0045] Considering that the dried Li3OCl may aggregate into agglomerates, the above preparation method further includes: grinding the dried Li3OCl.
[0046] Specifically, the grinding can be performed in an argon atmosphere glove box.
[0047] Compared with the prior art, the preparation method of the present invention dissolves the raw materials LiCl and Li2O in an ether organic solvent, so that the raw materials are fully in contact, the reaction rate is accelerated to generate Li3OCl solid electrolyte, and the ether solvent does not participate in the reaction, which can improve the purity of the product; the method is easy to operate and easy to commercialize and mass produce.
[0048] The preparation method of the invention avoids solid-phase high-temperature sintering and can reduce energy consumption; the invention has a high yield, for example, the yield can reach more than 94%, for example, 94.8% to 96%.
[0049] The Li3OCl obtained by the preparation method of the present invention has high purity and is free of impurities, with a purity close to 100%. The obtained Li3OCl has a wide electrochemical stability window of -1 to 9V, which can meet the commercial application requirements of high-voltage all-solid-state batteries.
[0050] The ether solvent of the present invention does not participate in the reaction and can be recycled, thereby further reducing the synthesis cost.
[0051] The technical solution of the present invention is further explained below in conjunction with specific examples. It should be noted that the data in the examples are all exemplary descriptions, and the dosage can be determined according to actual needs during the production process.
[0052] Example 1
[0053] This embodiment provides a method for preparing a Li3OCl solid electrolyte, comprising:
[0054] LiCl and Li2O were weighed in a 1:1 molar ratio (21.19 g LiCl and 14.94 g Li2O) and the weighed raw materials were placed in a clean PE bottle;
[0055] Add 85g of xylene ether, put into a sealed reactor, heat at 200°C for 22h, and stir once after 11h;
[0056] The filtered material was then placed in a vacuum tube furnace, dried at 200° C. for 4 h in a constant temperature vacuum oven, and then transferred to an argon atmosphere glove box for grinding to obtain 34.32 g of Li3OCl solid electrolyte (theoretical 36.13 g) with a purity close to 100%.
[0057] The yield of this embodiment is as high as 95%.
[0058] The flowchart of this embodiment is as follows Figure 1 shown.
[0059] Example 2
[0060] This embodiment provides a method for preparing a Li3OCl solid electrolyte, comprising:
[0061] Weigh LiCl and Li2O in a 1:1 molar ratio (31.79 g LiCl and 22.41 g Li2O) and place the weighed raw materials into a clean PE bottle;
[0062] Add 127.2 g of p-tert-butylanisole, put into a sealed reactor and heat at 200°C for 24 h. Stir once after 12 h.
[0063] The filtered material was then placed in a vacuum tube furnace and dried at 210° C. for 4 h in a constant temperature vacuum oven. The material was then transferred to an argon atmosphere glove box and ground to obtain 51.54 g of Li3OCl solid electrolyte (theoretical 54.2 g) with a purity close to 100%.
[0064] The yield of this embodiment is as high as 95.1%.
[0065] Example 3
[0066] This embodiment provides a method for preparing a Li3OCl solid electrolyte, comprising:
[0067] LiCl and Li2O were weighed in a 1:1 molar ratio (42.38 g LiCl and 29.88 g Li2O) and the weighed raw materials were placed in a clean PE bottle;
[0068] Add 170g of diphenyl ether, put into the reactor, seal it and heat at 210℃ for 26h, stir once after 13h;
[0069] The filtered material was then placed in a vacuum tube furnace, dried at 220° C. for 4 h in a constant temperature vacuum oven, and then transferred to an argon atmosphere glove box for grinding to obtain 68.5 g of Li3OCl solid electrolyte (theoretical 72.26 g) with a purity close to 100%.
[0070] The yield of this embodiment is as high as 94.8%.
[0071] The Li3OCl solid electrolyte of the embodiment was characterized by X-ray powder diffraction. Preparation of XRD test sample: the test sample is a ground powder material. First, take an appropriate amount of ground material in a glove box with an argon atmosphere and put it in the groove of a square glass sheet. Then use a thin glass sheet to compact and flatten the material, and seal it with a white transparent film to prevent the material from contacting with air and deteriorating. This test uses a Cu target material, working current: 40mA; working voltage: 40kV; scanning range: 10~75°.
[0072] like Figure 1 The XRD patterns of the products of Example 1 and Comparative Examples 1 to 5 are shown. It can be seen that the Li3OCl prepared in Example 1 has a higher crystallinity and is free of other impurities.
[0073] The Li3OCl solid electrolytes of Examples 2 and 3 were also characterized by X-ray powder diffraction, and the Li3OCl had a high degree of crystallinity and no other impurities.
[0074] The Li3OCl solid electrolyte of the embodiment was subjected to CV characterization. The assembly process of the cyclic voltammetry test battery was as follows: first, a thin stainless steel sheet was placed in the battery shell, the annealed solid electrolyte sheet was placed on the stainless steel sheet, then a fresh lithium sheet was placed on the solid electrolyte sheet, a thick stainless steel sheet was placed on the lithium sheet, and finally a spring sheet was placed to act as a buffer, and the battery was placed on a button battery sealing machine and sealed at 100MPa. The CV test adopted -1 to 9V scanning, and the scanning speed was 5mV / s. The electrochemical stability window of Li3OCl and the occurrence of side reactions were judged by observing the oxidation-reduction peak position.
[0075] Figure 3 The CV curve diagram of Example 1 is shown. The test results show that the Li3OCl synthesized in this example has a wide electrochemical stability window. Except for the redox peak of lithium appearing near 0V, no other impurity peaks are generated. Therefore, its electrochemical stability window can reach -1 to 9V, and it has good stability for both the anode and the cathode.
[0076] The Li3OCl solid electrolytes of Examples 2 and 3 were characterized by CV. The CV curves of Examples 2 and 3 are shown in FIG. Figure 3 It can be seen that the Li3OCl synthesized in Example 2 and Example 3 has a wide electrochemical stability window, and no other side reaction peaks are generated in the range of -1 to 9V.
[0077] The inventor has conducted a large number of experimental studies during the research process, and now uses some solutions with poor performance as comparative examples.
[0078] Comparative Example 1
[0079] This comparative example provides a method for preparing a Li3OCl solid electrolyte, the flow chart of which is as follows: Figure 4 As shown, the preparation method comprises:
[0080] LiCl and Li2O were weighed in a 1:1 molar ratio (21.19 g LiCl and 14.94 g Li2O), and the weighed raw materials were placed in a clean PE bottle, and an appropriate amount of 1-pentanol was added. The mixture was sealed in a reactor and heated at 130°C for 24 hours, during which the mixture was cooled and stirred once. The mixture was then filtered, dried in a vacuum tube furnace at 200°C for 4 hours, and then transferred to an argon atmosphere glove box for grinding to obtain 33.32 g of solid electrolyte.
[0081] The Li3OCl solid electrolyte obtained in Comparative Example 1 was characterized by X-ray powder diffraction. Figure 2 As shown, it can be seen that the solid electrolyte prepared by the method of Comparative Example 1 has a peak of the impurity Li2OHCl.
[0082] The Li3OCl solid electrolyte obtained in Comparative Example 1 was subjected to CV characterization. The CV curve is shown in Figure 3 As shown, it can be seen that the solid electrolyte prepared by the method of Comparative Example 1 has other peaks around 3.5V in addition to the lithium redox peak near 0V. It cannot maintain a stable state at high potential and cannot meet the requirements of high-potential all-solid-state batteries.
[0083] Comparative Example 2
[0084] This comparative example provides a method for preparing a Li3OCl solid electrolyte, the flow chart of which is as follows: Figure 5 As shown, the preparation method comprises:
[0085] LiCl and Li2O were weighed in a 1:1 molar ratio (21.19 g LiCl and 14.94 g Li2O), and the weighed raw materials were placed in a sealed reactor and heated at 400°C for 24 hours, during which cooling and grinding were performed once. Then 33 g of product containing the raw materials was obtained. The reaction temperature was high, the reaction was slow, and the yield was low.
[0086] The product was characterized by X-ray powder diffraction. Figure 2 As shown, it can be seen that the product prepared by the method of Comparative Example 2 is mainly the peak of raw materials Li2O and LiCl. This synthesis method has a slow reaction rate, a long preparation cycle, and a low yield, which is difficult to meet the requirements of commercial large-scale production.
[0087] Comparative Example 3
[0088] This comparative example provides a method for preparing a Li3OCl solid electrolyte. The overall steps of the preparation method are the same as those of Example 1, except that:
[0089] The mass ratio of the organic solvent to LiCl is 8:1, and 170 g of xylene ether is used.
[0090] from Figure 2 Characterization shows the peaks of residual Li2O and LiCl in the product, indicating that the reaction rate of this solvent ratio is slow and the reaction is not complete.
[0091] Comparative Example 4
[0092] This comparative example provides a method for preparing a Li3OCl solid electrolyte. The overall steps of the preparation method are the same as those of Example 1, except that:
[0093] The reaction temperature was 180°C.
[0094] from Figure 2 Characterization shows the peaks of residual Li2O and LiCl in the product, indicating that the reaction rate is slow at this reaction temperature and the reaction is not complete.
[0095] Comparative Example 5
[0096] This comparative example provides a method for preparing a Li3OCl solid electrolyte. The overall steps of the preparation method are the same as those of Example 1, except that:
[0097] The reaction time is 30h.
[0098] from Figure 2 Characterization shows that there is no residual Li2O and LiCl in the product, and the reaction is complete. The peak intensity of Li3OCl is weaker than that in Example 1, and the product structure is destroyed due to the long reaction time.
[0099] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.
Claims
1. A method for preparing a Li3OCl solid electrolyte, characterized in that: The preparation method comprises: The raw materials LiCl and Li2O are mixed, an ether organic solvent is added to react, and then filtered and dried to obtain a Li3OCl solid electrolyte.
2. The method for preparing the Li3OCl solid electrolyte according to claim 1, characterized in that: The ether organic solvent includes one or more of xylyl ether, p-tert-butylanisole and biphenyl ether.
3. The method for preparing the Li3OCl solid electrolyte according to claim 1, characterized in that: The mass ratio of the ether organic solvent to the LiCl is 3 to 5:
1.
4. The method for preparing the Li3OCl solid electrolyte according to claim 1, characterized in that: The reaction temperature is 190-220°C.
5. The method for preparing the Li3OCl solid electrolyte according to claim 4, characterized in that: The reaction time is 20 to 27 hours.
6. The method for preparing the Li3OCl solid electrolyte according to claim 1, characterized in that: Stirring was performed during the reaction.
7. The method for preparing the Li3OCl solid electrolyte according to claim 1, characterized in that: The drying is performed in a vacuum tube furnace.
8. The method for preparing the Li3OCl solid electrolyte according to claim 1, characterized in that: The drying temperature is 200-240°C.
9. The method for preparing the Li3OCl solid electrolyte according to claim 8, characterized in that: The drying time is 2 to 5 hours.
10. The method for preparing the Li3OCl solid electrolyte according to any one of claims 1 to 9, characterized in that: The preparation method further comprises: grinding the dried Li3OCl.