Method for realizing lithium-sodium solid electrolyte conversion, solid electrolyte and application

Abstract

The invention provides a method for realizing lithium-sodium solid electrolyte conversion, a solid electrolyte and application, and the method comprises the following steps: mixing a sodium-based solid electrolyte material, a lithium salt, a sodium ion complexing agent and a polar electrolyte, reacting, carrying out solid-liquid separation, and washing to obtain a first sodium-based precursor material; or carrying out mixing, reaction, solid-liquid separation and washing on the lithium-series solid electrolyte material, the sodium salt, the lithium ion complexing agent and the polar electrolyte to obtain a first lithium-series precursor material; and sintering the first sodium-series precursor material or the first lithium-series precursor material to realize lithium-sodium solid electrolyte conversion. According to the method, the polar electrolyte is used and combined with the corresponding ion complexing agent, so that conversion of lithium and sodium in the solid electrolyte material is realized, and process common communication and fusion between the lithium-series solid electrolyte and the sodium-series solid electrolyte are promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and relates to a method for realizing the conversion of lithium-sodium solid electrolytes, a solid electrolyte and applications thereof. Background Art

[0002] In recent years, with the drastic fluctuations in the price of lithium carbonate, a battery raw material, the potential of sodium-ion batteries with more significant cost advantages in the fields of energy storage and electric vehicles has been recognized by more and more people. Lithium and sodium, as alkali metal elements in the same group, have great similarities in physical and chemical properties. Currently, lithium-ion batteries dominate the new energy system, while sodium-ion batteries are potential alternative solutions that are expected to achieve larger-scale applications in certain fields. Achieving a good transition from lithium-ion batteries to sodium-ion batteries is an urgent issue to be considered under the change of the new energy system era, especially since solid-state batteries, as power batteries, have higher safety performance compared to liquid batteries.

[0003] In the prior art, a large number of lithium-based solid electrolytes have been disclosed, such as lithium lanthanum titanium oxide (LLTO, specifically Li 3x La 2 / 3-x TiO3), lithium germanium phosphorus sulfide (LGPS, specifically Li 10 GeP2S 12 ) and a series of lithium-based solid electrolyte materials. The application of sodium-based solid electrolytes to actual batteries has only recently begun to be attempted. Therefore, by means of a series of technologies, realizing the conversion between lithium and sodium in solid electrolytes can promote the integrated development of lithium / sodium-based batteries.

[0004] Moreover, in the research of lithium-based solid electrolytes and sodium-based solid electrolytes, the two are often separated. Lithium ions have high conductivity and energy density, but high costs. In the prior art, efforts have been made to promote the industrial development of lithium-based solid electrolytes from the perspective of cost reduction. Although sodium ions have relatively low conductivity and energy density, they are rich in resources and lower in cost. Therefore, the prior art is committed to optimizing the performance structure of sodium-based solid electrolytes to promote their application. Lithium-based solid electrolytes and sodium-based solid electrolytes have differences in chemical composition, ionic conductivity, stability, cost, application fields and manufacturing processes. These differences enable them to play their respective advantages in different battery technologies and applications. Therefore, from the perspective of maximizing the rational utilization of resources, a method for realizing the conversion of lithium-sodium solid electrolytes is needed to promote the process commonality and integration between lithium-based solid electrolytes and sodium-based solid electrolytes. Summary of the Invention

[0005] The object of the present invention is to provide a method for realizing the conversion of lithium-sodium solid electrolytes, a solid electrolyte and an application thereof. By using a polar electrolyte and combining with a corresponding ion complexing agent, the conversion of lithium and sodium in the solid electrolyte material is realized, and the process commonality and integration between lithium-based solid electrolytes and sodium-based solid electrolytes are promoted.

[0006] To achieve the object of the present invention, the following technical solutions are adopted:

[0007] In the first aspect, the present invention provides a method for realizing the conversion of lithium-sodium solid electrolytes, and the method comprises the following steps:

[0008] (1) Mix, react, separate solid from liquid and wash a sodium-based solid electrolyte material, a lithium salt, a sodium ion complexing agent and a polar electrolyte to obtain a first sodium-based precursor material;

[0009] Alternatively, mix, react, separate solid from liquid and wash a lithium-based solid electrolyte material, a sodium salt, a lithium ion complexing agent and a polar electrolyte to obtain a first lithium-based precursor material;

[0010] (2) Sinter the first sodium-based precursor material or the first lithium-based precursor material obtained in step (1) to realize the conversion of lithium-sodium solid electrolytes.

[0011] The present invention uses a polar electrolyte as a medium to promote the process integration between lithium-based solid electrolytes and sodium-based solid electrolytes. When converting the sodium-based solid electrolyte material into a lithium-based solid electrolyte material, a sodium ion complexing agent is added. When lithium ions and sodium ions coexist, the sodium ion complexing agent selectively complexes sodium ions, thereby promoting the removal of sodium ions from the sodium-based solid electrolyte material and promoting the formation of the lithium-based solid electrolyte material, so that the deep conversion of lithium-sodium solid electrolytes can be realized; similarly, when converting the lithium-based solid electrolyte material into a sodium-based solid electrolyte material, a lithium ion complexing agent is added to selectively complex lithium ions and promote the formation of the sodium-based solid electrolyte material. Therefore, the method of the present invention not only has a simple process, but also can realize the deep conversion of lithium and sodium.

[0012] The mixing, reacting, etc. of the sodium-based solid electrolyte material, the lithium salt, the sodium ion complexing agent and the polar electrolyte in the present invention are to convert the sodium-based solid electrolyte material into a lithium-based solid electrolyte material; the mixing, reacting, etc. of the lithium-based solid electrolyte material, the sodium salt, the lithium ion complexing agent and the polar electrolyte are to convert the lithium-based solid electrolyte material into a sodium-based solid electrolyte material.

[0013] Preferably, the molar ratio of the sodium ion complexing agent described in step (1) to the sodium ions in the sodium-based solid electrolyte material is (1.5 - 2.5):1. For example, it can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1 or 2.5:1. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0014] Preferably, the molar ratio of the lithium ion complexing agent described in step (1) to the lithium ions in the lithium-based solid electrolyte material is (1.5 - 2.5):1. For example, it can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1 or 2.5:1. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0015] The sodium ion complexing agent or lithium ion complexing agent added in the present invention needs to cooperate with the ions in the solid electrolyte material. If too little complexing agent is added, the effect of complexing ions will be reduced, affecting the conversion efficiency of lithium and sodium. If too much complexing agent is added, since lithium ions and sodium ions have similar properties, the sodium ion complexing agent may complex lithium ions, and the lithium ion complexing agent may complex sodium ions, affecting the conversion efficiency of lithium and sodium.

[0016] Preferably, the sodium ion complexing agent described in step (1) includes any one or a combination of at least two of 15-crown-5, 18-crown-6 or sulfonated calix[4]arene.

[0017] Preferably, the lithium ion complexing agent described in step (1) includes dibenzo-14-crown-4 and / or [2.1.1]-cryptand.

[0018] The sodium ion complexing agent of the present invention is a complexing agent that selectively complexes sodium ions and has a high selectivity for complexing sodium ions; the lithium ion complexing agent is a complexing agent that selectively complexes lithium ions and has a high selectivity for complexing lithium ions.

[0019] Preferably, the polar electrolyte described in step (1) includes any one or a combination of at least two of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C8H 11 F6N3O4S2, EMIMTFSI), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C 10 H 15 F6N3O4S2) or 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (C6H 11 F2N3O4S2).

[0020] The present invention uses a strongly polar organic electrolyte to enable ion exchange of each raw material. Through the contact exchange between the macroscopic raw materials in the solid-liquid state, Na + and Li + efficiency replacement effect is achieved microscopically.

[0021] Preferably, the lithium salt in step (1) includes any one or a combination of at least two of lithium bis(trifluoromethanesulfonyl)imide (C2F6LiNO4S2, LiTFSI), lithium bis(fluorosulfonyl)imide (F2LiNO4S2), lithium bis(nonafluorobutanesulfonyl)imide (C8F 18 LiNO4S2), or lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide (CF4LiNO4S2).

[0022] Preferably, the sodium-based solid electrolyte material in step (1) includes any one or a combination of at least two of sodium zirconium phosphate (NaZr2(PO4)3, NZP), sodium titanium phosphate (NaTi2(PO4)3, NTP), sodium germanium phosphate (NaGe2(PO4)3, NGP), sodium lanthanum titanium oxide (Na 3x La 2 / 3-x TiO3, NLTO), sodium lanthanum zirconium oxide (Na7La3Zr2O 12 , NLZO), sodium zirconium phosphate silicate electrolyte (Na3Zr2Si2PO 12 , NZPS), or sodium germanium phosphorus sulfide (Na 10 GeP2S 12 , NGPS).

[0023] Preferably, the sodium salt in step (1) includes any one or a combination of at least two of sodium bis(trifluoromethanesulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium bis(nonafluorobutanesulfonyl)imide, or sodium (fluorosulfonyl)(trifluoromethanesulfonyl)imide.

[0024] Preferably, the lithium-based solid electrolyte material in step (1) includes any one or a combination of at least two of lithium zirconium phosphate, lithium titanium phosphate, lithium germanium phosphate, lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, lithium zirconium phosphate silicate electrolyte, or lithium germanium phosphorus sulfide.

[0025] Preferably, the molar ratio of the sodium-based solid electrolyte material to the lithium salt in step (1) is 1:(1 - 5). For example, it can be 1:1, 1:2, 1:3, 1:4, or 1:5, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0026] Preferably, the molar ratio of the lithium-based solid electrolyte material to the sodium salt in step (1) is 1:(1 - 5). For example, it can be 1:1, 1:2, 1:3, 1:4, or 1:5, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0027] Preferably, the mass ratio of the sodium-based solid electrolyte material to the polar electrolyte in step (1) is 1:(20 - 30). For example, it can be 1:20, 1:25, or 1:30, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0028] Preferably, the mass ratio of the lithium-based solid electrolyte material to the polar electrolyte in step (1) is 1:(20 - 30). For example, it can be 1:20, 1:25, or 1:30, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0029] Preferably, the temperature of the reaction in step (1) is 120 - 200 °C. For example, it can be 120 °C, 140 °C, 160 °C, 180 °C, or 200 °C, the time is 8 - 40 h. For example, it can be 8 h, 10 h, 20 h, 30 h, or 40 h, and the stirring speed is 20 - 100 rpm. For example, it can be 20 rpm, 40 rpm, 60 rpm, 80 rpm, or 100 rpm, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0030] Preferably, when the first sodium-based precursor material in step (1) is used as the sodium-based solid electrolyte material, after repeating step (1) more than once (for example, step (1) can be repeated once, twice, three times, or four times), sintering is carried out, and no sodium ion complexing agent is added during the repetition.

[0031] Preferably, when the first lithium-based precursor material in step (1) is used as the lithium-based solid electrolyte material, after repeating step (1) more than once (for example, step (1) can be repeated once, twice, three times, or four times), sintering is carried out, and no lithium ion complexing agent is added during the repetition.

[0032] When the present invention converts the sodium-based solid electrolyte material into the lithium-based solid electrolyte material, no sodium ion complexing agent is added during the repeated reaction. Because when the reaction is repeated, the content of lithium ions in the system is relatively high and the content of sodium ions is relatively low, the probability of the sodium ion complexing agent complexing lithium ions increases. Therefore, the probability of complexing out the already converted ions increases, thereby reducing the conversion efficiency. Similarly, when converting the lithium-based solid electrolyte material into the sodium-based solid electrolyte material, no lithium ion complexing agent is added during the repeated reaction.

[0033] Preferably, the method further includes the following steps:

[0034] Before the sintering, the first sodium-based precursor material, lithium salt, and polar electrolyte described in step (1) are mixed, reacted, solid-liquid separated, and washed to obtain a second sodium-based precursor material;

[0035] The second sodium-based precursor material, lithium salt, and polar electrolyte are continuously mixed, reacted, solid-liquid separated, and washed to obtain a third sodium-based precursor material;

[0036] Alternatively, a first lithium-based precursor material, sodium salt, and polar electrolyte are mixed, reacted, solid-liquid separated, and washed to obtain a second lithium-based precursor material;

[0037] The second lithium-based precursor material, sodium salt, and polar electrolyte are continuously mixed, reacted, solid-liquid separated, and washed to obtain a third lithium-based precursor material.

[0038] Preferably, step (1) is carried out three times in total in the present invention. When carried out three times, the molar ratio of raw materials, reaction time, and temperature can be the same or different.

[0039] Preferably, the reaction temperature of the first sodium-based precursor material, lithium salt, and polar electrolyte is higher than the reaction temperature of the second sodium-based precursor material, lithium salt, and polar electrolyte, and higher than the reaction temperature of the sodium-based solid electrolyte material, lithium salt, sodium ion complexing agent, and polar electrolyte.

[0040] Preferably, the reaction temperature of the first lithium-based precursor material, sodium salt, and polar electrolyte is higher than the reaction temperature of the second lithium-based precursor material, sodium salt, and polar electrolyte, and higher than the reaction temperature of the lithium-based solid electrolyte material, sodium salt, lithium ion complexing agent, and polar electrolyte.

[0041] When the reaction of step (1) is carried out three times repeatedly in the present invention, preferably the temperature of the second time is the highest. The first reaction is carried out rapidly in the presence of a complexing agent to initially achieve exchange. No complexing agent is added during the second reaction, so as to increase the temperature to achieve deep exchange of lithium ions and sodium ions. During the last reaction, while further promoting lithium-sodium exchange, the stability of ions in the generated solid electrolyte material is ensured, so the temperature is lower than that of the second reaction. While improving the lithium-sodium conversion efficiency, the stability of the generated material is ensured.

[0042] Preferably, the temperature for the reaction of the first sodium-based precursor material, lithium salt, and polar electrolyte is 160 - 200 °C. For example, it can be 160 °C, 170 °C, 180 °C, 190 °C, or 200 °C. The temperatures for the reactions of the second sodium-based precursor material, lithium salt, and polar electrolyte, and the sodium-based solid electrolyte material, lithium salt, sodium ion complexing agent, and polar electrolyte are each independently 120 - 150 °C. For example, it can be 120 °C, 130 °C, 140 °C, or 150 °C. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0043] Preferably, the temperature for the reaction of the first lithium-based precursor material, sodium salt, and polar electrolyte is 160 - 200 °C. For example, it can be 160 °C, 170 °C, 180 °C, 190 °C, or 200 °C. The temperatures for the reactions of the second lithium-based precursor material, sodium salt, and polar electrolyte, and the lithium-based solid electrolyte material, sodium salt, lithium ion complexing agent, and polar electrolyte are each independently 120 - 150 °C. For example, it can be 120 °C, 130 °C, 140 °C, or 150 °C. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0044] Preferably, the temperature for the sintering in step (2) is 100 - 700 °C. For example, it can be 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, or 700 °C. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0045] Preferably, the time for the sintering in step (2) is 1 - 20 h. For example, it can be 1 h, 5 h, 10 h, 15 h, or 20 h.

[0046] In a second aspect, the present invention provides a solid electrolyte, which is prepared by the method as described in the first aspect.

[0047] In a third aspect, the present invention provides a solid-state battery, which includes the solid electrolyte as described in the second aspect.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The present invention uses a polar electrolyte as a medium to promote the process integration between lithium-based solid electrolytes and sodium-based solid electrolytes. When converting sodium-based solid electrolyte materials into lithium-based solid electrolyte materials, a sodium ion complexing agent is added. When lithium ions and sodium ions coexist, the sodium ion complexing agent selectively complexes sodium ions, thereby promoting the removal of sodium ions from the sodium-based solid electrolyte materials and promoting the formation of lithium-based solid electrolyte materials, enabling the deep conversion of lithium-sodium solid electrolytes. Similarly, when converting lithium-based solid electrolyte materials into sodium-based solid electrolyte materials, a lithium ion complexing agent is added to selectively complex lithium ions and promote the formation of sodium-based solid electrolyte materials. Therefore, the method of the present invention not only has a simple process but also can achieve the deep conversion of lithium and sodium. Detailed Embodiments

[0050] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0051] Example 1

[0052] This example provides a method for realizing the conversion of lithium-sodium solid electrolytes. The method includes the following steps:

[0053] (1) Mix the sodium-based solid electrolyte material, lithium salt, sodium ion complexing agent, and polar electrolyte. In a homogeneous reactor, react at a temperature of 130 °C and a stirring speed of 80 rpm for 24 h. Centrifuge the obtained suspension at 20,000 rpm for 5 min, and wash the precipitate with anhydrous ethanol three times to obtain the first sodium-based precursor material;

[0054] Among them, the molar ratio of the sodium ion complexing agent to sodium ions in the sodium-based solid electrolyte material is 2:1, the molar ratio of the sodium-based solid electrolyte material to the lithium salt is 1:5, and the mass ratio of the sodium-based solid electrolyte material to the polar electrolyte is 1:25;

[0055] (2) Mix the first sodium-based precursor material, lithium salt, and polar electrolyte obtained in step (1). In a homogeneous reactor, react at a temperature of 180 °C and a stirring speed of 70 rpm for 20 h. Centrifuge the obtained suspension at 20,000 rpm for 5 min, and wash the precipitate with anhydrous ethanol three times to obtain the second sodium-based precursor material;

[0056] Among them, the molar ratio of the first sodium-based precursor material to the lithium salt is 1:4, and the mass ratio of the first sodium-based precursor material to the polar electrolyte is 1:25;

[0057] (3) Mix the second sodium-based precursor material, lithium salt, and polar electrolyte described in step (2), and react in a homogeneous reactor at a temperature of 130 °C and a stirring speed of 80 rpm for 24 h. Centrifuge the resulting suspension at 20,000 rpm for 5 min, and wash the precipitate with anhydrous ethanol three times to obtain the third sodium-based precursor material;

[0058] Among them, the molar ratio of the second sodium-based precursor material to the lithium salt is 1:5, and the mass ratio of the second sodium-based precursor material to the polar electrolyte is 1:25;

[0059] In steps (1), (2), and (3), the sodium-based solid electrolyte material is Na3Zr2Si2PO 12 , the lithium salt is lithium bis(trifluoromethanesulfonyl)imide, the sodium ion complexing agent is 15-crown-5, and the polar electrolyte is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide;

[0060] (4) Sinter the third sodium-based precursor material described in step (3) at 500 °C for 5 h to achieve the conversion of lithium-sodium solid electrolyte and obtain the lithium-based solid electrolyte material.

[0061] Example 2

[0062] This example provides a method for realizing the conversion of lithium-sodium solid electrolyte. The method includes the following steps:

[0063] (1) Mix the sodium-based solid electrolyte material, lithium salt, sodium ion complexing agent, and polar electrolyte, and react in a homogeneous reactor at a temperature of 150 °C and a stirring speed of 40 rpm for 40 h. Centrifuge the resulting suspension at 20,000 rpm for 5 min, and wash the precipitate with anhydrous ethanol three times to obtain the first sodium-based precursor material;

[0064] Among them, the molar ratio of the sodium ion complexing agent to the sodium ions in the sodium-based solid electrolyte material is 1.5:1, the molar ratio of the sodium-based solid electrolyte material to the lithium salt is 1:2, and the mass ratio of the sodium-based solid electrolyte material to the polar electrolyte is 1:30;

[0065] (2) Mix the first sodium-based precursor material, lithium salt, and polar electrolyte described in step (1), and react in a homogeneous reactor at a temperature of 170 °C and a stirring speed of 100 rpm for 10 h. Centrifuge the resulting suspension at 20,000 rpm for 5 min, and wash the precipitate with anhydrous ethanol three times to obtain the second sodium-based precursor material;

[0066] Among them, the molar ratio of the first sodium-based precursor material to the lithium salt is 1:2, and the mass ratio of the first sodium-based precursor material to the polar electrolyte is 1:20;

[0067] (3) Mix the second sodium-based precursor material, lithium salt, and polar electrolyte described in step (2), and react in a homogeneous reactor at a temperature of 150 °C and a stirring speed of 40 rpm for 10 h. Centrifuge the resulting suspension at 20000 rpm for 5 min, and wash the precipitate with absolute ethanol three times to obtain the third sodium-based precursor material;

[0068] Among them, the molar ratio of the second sodium-based precursor material to the lithium salt is 1:2, and the mass ratio of the second sodium-based precursor material to the polar electrolyte is 1:30;

[0069] In steps (1), (2), and (3), the sodium-based solid electrolyte material is Na3Zr2Si2PO 12 , the lithium salt is lithium bis(trifluoromethanesulfonyl)imide, the sodium ion complexing agent is 15-crown-5, and the polar electrolyte is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide;

[0070] (4) Sinter the third sodium-based precursor material described in step (3) at 700 °C for 2 h to achieve the conversion of lithium-sodium solid electrolyte and obtain the lithium-based solid electrolyte material.

[0071] Example 3

[0072] This example provides a method for realizing the conversion of lithium-sodium solid electrolyte. The method includes the following steps:

[0073] (1) Mix the lithium-based solid electrolyte material, sodium salt, lithium ion complexing agent, and polar electrolyte, and react in a homogeneous reactor at a temperature of 120 °C and a stirring speed of 100 rpm for 10 h. Centrifuge the resulting suspension at 20000 rpm for 5 min, and wash the precipitate with absolute ethanol three times to obtain the first lithium-based precursor material;

[0074] Among them, the molar ratio of the lithium ion complexing agent to the lithium ions in the lithium-based solid electrolyte material is 2.5:1, the molar ratio of the lithium-based solid electrolyte material to the sodium salt is 1:5, and the mass ratio of the lithium-based solid electrolyte material to the polar electrolyte is 1:20;

[0075] (2) Mix the first lithium-based precursor material, sodium salt, and polar electrolyte described in step (1), and react in a homogeneous reactor at a temperature of 200 °C and a stirring speed of 40 rpm for 40 h. Centrifuge the resulting suspension at 20000 rpm for 5 min, and wash the precipitate with absolute ethanol three times to obtain the second lithium-based precursor material;

[0076] Among them, the molar ratio of the first lithium-based precursor material to the sodium salt is 1:5, and the mass ratio of the first lithium-based precursor material to the polar electrolyte is 1:30;

[0077] (3) Mix the second lithium-based precursor material, the sodium salt, and the polar electrolyte described in step (2). In a homogeneous reactor, react at a temperature of 120 °C and a stirring speed of 100 rpm for 40 h. Centrifuge the obtained suspension at 20,000 rpm for 5 min, and wash the precipitate with anhydrous ethanol three times to obtain the third lithium-based precursor material;

[0078] Among them, the molar ratio of the second lithium-based precursor material to the sodium salt is 1:1, and the mass ratio of the second lithium-based precursor material to the polar electrolyte is 1:20;

[0079] In steps (1), (2), and (3), the lithium-based solid electrolyte material is Li 0.33 La 0.56 TiO3, the sodium salt is sodium bis(trifluoromethanesulfonyl)imide, the lithium ion complexing agent is dibenzo-14-crown-4, and the polar electrolyte is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide;

[0080] (4) Sinter the third lithium-based precursor material described in step (3) at 300 °C for 20 h to achieve the conversion of lithium-sodium solid electrolyte and obtain the sodium-based solid electrolyte material.

[0081] Example 4

[0082] This example provides a method for realizing the conversion of lithium-sodium solid electrolyte. Except that the molar ratio of the sodium ion complexing agent to the sodium ions in the sodium-based solid electrolyte material in step (1) is 1:1, the rest are the same as in Example 1.

[0083] Example 5

[0084] This example provides a method for realizing the conversion of lithium-sodium solid electrolyte. Except that the molar ratio of the sodium ion complexing agent to the sodium ions in the sodium-based solid electrolyte material in step (1) is 3:1, the rest are the same as in Example 1.

[0085] Example 6

[0086] This example provides a method for realizing the conversion of lithium-sodium solid electrolyte. Except that a sodium ion complexing agent is further added in steps (2) and (3), and the molar ratio of the sodium ion complexing agent to the sodium ions in the first sodium-based precursor material is 2:1, and the molar ratio of the sodium ion complexing agent to the sodium ions in the second sodium-based precursor material is 2:1, the rest are the same as in Example 1.

[0087] Example 7

[0088] This embodiment provides a method for realizing the conversion of lithium-sodium solid electrolyte. Except that the reaction temperatures in steps (1), (2), and (3) are all 130 °C, the rest are the same as those in Embodiment 1.

[0089] Embodiment 8

[0090] This embodiment provides a method for realizing the conversion of lithium-sodium solid electrolyte. Except that steps (2) and (3) are not carried out, the rest are the same as those in Embodiment 1.

[0091] Comparative Example 1

[0092] This comparative example provides a method for realizing the conversion of lithium-sodium solid electrolyte. Except that no sodium ion complexing agent is added in step (1), the rest are the same as those in Embodiment 1.

[0093] Calculate the lithium-sodium conversion rates of the above embodiments and comparative examples. The calculation method is (converted ion concentration / fixed ion concentration) × 100%, where the converted ion concentration refers to the ion concentration that has been converted per unit volume of the solution, and the fixed ion concentration refers to the original ion concentration that has not been converted per unit volume of the solution. The calculated lithium-sodium conversion rates are shown in Table 1:

[0094] Table 1

[0095]

[0096]

[0097] As can be seen from Table 1:

[0098] From Embodiment 1 and Comparative Example 1, it can be seen that the present invention preferably adds a complexing agent with the same ion type as the solid electrolyte to be converted during the reaction in step (1) to promote the conversion of sodium ions and lithium ions and improve the lithium-sodium conversion rate; from Embodiment 1 and Embodiments 4-5, it can be seen that the present invention preferably controls the molar ratio of the complexing agent added in step (1) to the corresponding ions in the solid electrolyte material within a specific range, thereby further improving the lithium-sodium conversion rate; from Embodiment 1 and Embodiment 6, it can be seen that the present invention preferably adds the complexing agent only during the first reaction to avoid complexing out the already converted ions later, thereby further ensuring the lithium-sodium conversion rate; from Embodiment 1 and Embodiment 7, it can be seen that the present invention preferably sets the highest temperature during the reaction in step (2) to promote the deep exchange of lithium and sodium, and enables each reaction to play a specific role, enhancing the cooperative effect of multiple reactions, thereby further improving the lithium-sodium conversion rate; from Embodiment 1 and Embodiment 8, it can be seen that the present invention preferably performs three reactions to promote the deep exchange of lithium and sodium, and promote the stability of the generated solid electrolyte material, thereby improving the lithium-sodium conversion rate.

[0099] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for realizing the conversion of lithium-sodium solid electrolyte, characterized in that, The method comprises the following steps: (1) Mix, react, separate solid from liquid, and wash a sodium-based solid electrolyte material, a lithium salt, a sodium ion complexing agent, and a polar electrolyte to obtain a first sodium-based precursor material; Alternatively, mix, react, separate solid from liquid, and wash a lithium-based solid electrolyte material, a sodium salt, a lithium ion complexing agent, and a polar electrolyte to obtain a first lithium-based precursor material; (2) Sinter the first sodium-based precursor material or the first lithium-based precursor material obtained in step (1) to achieve the conversion of lithium-sodium solid electrolyte.

2. The method according to claim 1, wherein The molar ratio of the sodium ion complexing agent to the sodium ions in the sodium-based solid electrolyte material in step (1) is (1.5 - 2.5):1; Preferably, the molar ratio of the lithium ion complexing agent to the lithium ions in the lithium-based solid electrolyte material in step (1) is (1.5 - 2.5):

1.

3. The method according to claim 1 or 2, characterized in that, The sodium ion complexing agent in step (1) includes any one or a combination of at least two of 15-crown-5, 18-crown-6, or sulfonated calix[4]arene; Preferably, the lithium ion complexing agent in step (1) includes dibenzo-14-crown-4 and / or [2.1.1]-cryptand; Preferably, the polar electrolyte in step (1) includes any one or a combination of at least two of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, or 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide; Preferably, the lithium salt in step (1) includes any one or a combination of at least two of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium bis(nonafluorobutanesulfonyl)imide, or lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide; Preferably, the sodium-based solid electrolyte material in step (1) includes any one or a combination of at least two of sodium zirconium phosphate, sodium titanium phosphate, sodium germanium phosphate, sodium lanthanum titanium oxide, sodium lanthanum zirconium oxide, sodium zirconium phosphate silicate electrolyte, or sodium germanium phosphorus sulfide; Preferably, the sodium salt in step (1) includes any one or a combination of at least two of sodium bis(trifluoromethanesulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium bis(nonafluorobutanesulfonyl)imide, or sodium (fluorosulfonyl)(trifluoromethanesulfonyl)imide; Preferably, the lithium-based solid electrolyte material in step (1) includes any one or a combination of at least two of lithium zirconium phosphate, lithium titanium phosphate, lithium germanium phosphate, lithium lanthanum titanium oxide, lithium lanthanum zirconium oxide, lithium zirconium phosphate silicate electrolyte, or lithium germanium phosphorus sulfide.

4. The method according to any one of claims 1 to 3, characterized in that, The molar ratio of the sodium-based solid electrolyte material to the lithium salt in step (1) is 1:(1 - 5); Preferably, the molar ratio of the lithium-based solid electrolyte material to the sodium salt in step (1) is 1:(1 - 5); Preferably, the mass ratio of the sodium-based solid electrolyte material to the polar electrolyte in step (1) is 1:(20 - 30); Preferably, the mass ratio of the lithium-based solid electrolyte material to the polar electrolyte in step (1) is 1:(20 - 30); Preferably, the temperature of the reaction in step (1) is 120 - 200°C, the time is 8 - 40 h, and the stirring speed is 20 - 100 rpm.

5. The method according to any one of claims 1-4, characterized in that, The first sodium-based precursor material in step (1) is used as a sodium-based solid electrolyte material. After repeating step (1) more than once, sintering is carried out, and no sodium ion complexing agent is added during the repetition. Preferably, the first lithium-based precursor material in step (1) is used as a lithium-based solid electrolyte material. After repeating step (1) more than once, sintering is carried out, and no lithium ion complexing agent is added during the repetition.

6. The method according to claim 5, wherein The method further includes the following steps: Before the sintering, the first sodium-based precursor material, a lithium salt, and a polar electrolyte solution in step (1) are mixed, reacted, subjected to solid-liquid separation, and washed to obtain a second sodium-based precursor material. Subsequently, the second sodium-based precursor material, the lithium salt, and the polar electrolyte solution are further mixed, reacted, subjected to solid-liquid separation, and washed to obtain a third sodium-based precursor material. Alternatively, the first lithium-based precursor material, a sodium salt, and the polar electrolyte solution are mixed, reacted, subjected to solid-liquid separation, and washed to obtain a second lithium-based precursor material. Subsequently, the second lithium-based precursor material, the sodium salt, and the polar electrolyte solution are further mixed, reacted, subjected to solid-liquid separation, and washed to obtain a third lithium-based precursor material.

7. The method according to claim 6, wherein The reaction temperature of the first sodium-based precursor material, the lithium salt, and the polar electrolyte solution is higher than the reaction temperature of the second sodium-based precursor material, the lithium salt, and the polar electrolyte solution, and is higher than the reaction temperature of the sodium-based solid electrolyte material, the lithium salt, the sodium ion complexing agent, and the polar electrolyte solution. Preferably, the reaction temperature of the first lithium-based precursor material, the sodium salt, and the polar electrolyte solution is higher than the reaction temperature of the second lithium-based precursor material, the sodium salt, and the polar electrolyte solution, and is higher than the reaction temperature of the lithium-based solid electrolyte material, the sodium salt, the lithium ion complexing agent, and the polar electrolyte solution.

8. The method according to any one of claims 1 to 7, characterized in that, The sintering temperature in step (2) is 100 - 700 °C. Preferably, the sintering time in step (2) is 1 - 20 h.

9. A solid electrolyte, characterized in that, The solid electrolyte is prepared by the method according to any one of claims 1 - 8.

10. A solid-state battery, characterized in that, The solid-state battery includes the solid electrolyte according to claim 9.

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