Solid electrolyte, preparation method and lithium battery
By using a solid electrolyte composed of nitrate ionic liquid-based metal-organic framework C and polyethylene oxide and LiTFSI, the problem of lithium dendrite growth caused by SEI film inhomogeneity in lithium metal batteries was solved, improving the interface stability and safety of the battery and extending its cycle life.
Patent Information
- Application Number
- CN202512032980.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-02-27
AI Technical Summary
In lithium metal batteries, the uneven distribution of ion flow caused by the non-uniform structure of the SEI film during repeated lithium metal deposition/stripping leads to uncontrolled growth of lithium dendrites, increasing the risk of battery puncture and affecting cycle performance.
A solid electrolyte composed of nitrate ionic liquid-based metal-organic framework C, polyethylene oxide, and LiTFSI is used to promote the dissociation of lithium salt and form lithium nitride in situ on the surface of lithium metal anode through the binding effect of nitrogen-containing heterocycles with TFSI- anions in lithium salt, thus constructing a uniform SEI film.
It significantly improves the interface stability and safety of the battery, inhibits lithium dendrite growth, and extends the cycle life of the battery.
Smart Images
Figure CN121584019A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of lithium metal batteries, and particularly relates to a solid electrolyte, a preparation method thereof, and a lithium battery. Background Technology
[0002] In lithium metal batteries, the electrolyte and lithium metal anode undergo a reduction reaction during the first charge-discharge cycle to form an electrolyte interphase (SEI). The SEI is a multilayered heterogeneous structure primarily composed of inorganic components (such as LiF, Li3N, and Li2CO3) and organic components (such as alkyl lithium carbonate). An ideal SEI protects the anode structure and improves coulombic efficiency, while also helping to reduce the inhomogeneity of lithium deposition, thereby suppressing lithium dendrite growth. However, in reality, during repeated lithium metal deposition / stripping, the SEI film suffers from uneven ion flow distribution due to structural inhomogeneity, leading to uncontrolled and rapid lithium dendrite growth and eventual rupture. The exposed fresh lithium surface after rupture continuously consumes electrolyte to generate a new SEI film, resulting in irreversible loss of active lithium and electrolyte, forming "dead lithium" and exacerbating interfacial impedance. This problem increases the safety risk of battery puncture and severely affects the battery's cycle performance. Summary of the Invention
[0003] This application provides a solid electrolyte comprising a nitrate ionic liquid-based metal-organic framework C, polyethylene oxide, and LiTFSI, wherein the nitrate ionic liquid-based metal-organic framework C accounts for 3 wt% of the polyethylene oxide, and the molar ratio of the polyethylene oxide to LiTFSI is 10:1; wherein... The nitrate ion liquid-based metal-organic framework C has a nitrogen-containing heterocycle, on which nitrate ions and Zn ions are coordinated.
[0004] Another aspect of this application proposes a method for preparing a solid electrolyte, used to prepare the solid electrolyte in the above-mentioned technical solution, comprising the following steps: S1. Add the nitrogen-containing heterocyclic compound and 1-chlorobutane to methanol, stir, remove methanol by rotary evaporation, and dry to obtain ionic liquid A; S2. Add the ionic liquid A and sodium nitrate to methanol, stir, rotary evaporate, and dry to obtain nitrate ionic liquid B; S3. Add the nitrate ionic liquid B and zinc acetate to methanol, stir, filter out the solid, wash and dry the solid to obtain a porous, powdered nitrate ionic liquid-based metal-organic framework C. S4. Add the nitrate ionic liquid-based metal-organic framework C and LiTFSI to acetonitrile and stir to obtain the first mixture; Polyethylene oxide is added to the first mixture and stirred to obtain the second mixture; The second mixture was dried to obtain a solid electrolyte containing a liquid-based metal-organic framework of nitrate ions.
[0005] Furthermore, the nitrogen-containing heterocyclic compound includes one or both of 6-bromo-4-hydro-imidazo[4,5-B]pyridine and 1H-imidazo[4,5-B]pyrazine.
[0006] Furthermore, in step S1, the molar ratio of the nitrogen heterocyclic compound to 1-chlorobutane is 1:1 to 1.1.
[0007] Furthermore, in step S2, the molar ratio of ionic liquid A to sodium nitrate is 1:1 to 1.1.
[0008] Further, in step S3, the molar ratio of the nitrate ionic liquid B to zinc acetate is 4:1.
[0009] Furthermore, in step S1, the mixture is stirred for 24 hours at a temperature of 55–70°C; the drying temperature is 60°C. In step S2, the mixture is stirred for 24 hours at a temperature of 50–65°C; the drying temperature is 60°C. In step S3, the mixture is stirred for 12 hours; the drying temperature is 80℃. Step S4: Stir for 2 hours when preparing the first mixture; The second mixture was stirred for 12 h, naturally dried for 2 h, and then vacuum dried for 24 h.
[0010] Another aspect of this application proposes a lithium battery comprising the solid electrolyte described in the above technical solution, or a solid electrolyte prepared by the solid electrolyte preparation method described in the above technical solution.
[0011] The above-described technical solution of the present invention has at least the following beneficial technical effects: In the solid electrolyte of this application, the nitrogen-containing heterocyclic cations in the nitrate ion liquid-based metal-organic framework bind the TFSI- anions in the lithium salt, while simultaneously promoting lithium salt dissociation to generate lithium fluoride in situ. Furthermore, nitrate ions gain electrons on the lithium metal anode surface and combine with lithium ions to form lithium nitride in situ within the SEI layer, thereby reducing dead lithium deposition and ultimately significantly improving the battery's interface stability. This high-quality SEI film can uniformly conduct Li... + This promotes uniform lithium deposition, thereby effectively suppressing the growth of lithium dendrites and greatly improving the safety and cycle life of lithium batteries. Attached Figure Description
[0012] To more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0013] Figure 1 It is the ionic conductivity of the electrolyte in Example 1 and Comparative Example 1 of this application.
[0014] Figure 2 It is the ion transport number of the electrolyte in Example 1 and Comparative Example 1 of this application.
[0015] Figure 3 It is the critical current density of the electrolyte in Example 1 and Comparative Example 1 of this application.
[0016] Figure 4 The cycling performance of lithium symmetric batteries prepared with electrolytes in Example 1 and Comparative Example 1 of this application is shown.
[0017] Figure 5 The cycling performance of lithium iron phosphate full batteries prepared with the electrolytes in Example 1 and Comparative Example 1 of this application is shown.
[0018] Figure 6 This is the XPS energy spectrum of the electrolyte in an embodiment of this application.
[0019] Figure 7 This refers to the ionic conductivity of the electrolytes prepared in Examples 2 and 1 of this application.
[0020] Figure 8 It is the ion transport number of the electrolytes prepared in Example 2 and Comparative Example 1 of this application.
[0021] Figure 9 The cycling performance of the lithium-symmetric battery prepared with the electrolyte in Example 2 and Comparative Example 1 of this application is shown. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.
[0023] This application provides a solid electrolyte comprising a nitrate ion liquid-based metal-organic framework C, polyethylene oxide, and LiTFSI, wherein the nitrate ion liquid-based metal-organic framework C accounts for 3 wt% of polyethylene oxide, and the molar ratio of polyethylene oxide to LiTFSI is 10:1; wherein the nitrate ion liquid-based metal-organic framework C has a nitrogen-containing heterocycle, and nitrate ions and Zn ions are coordinated on the nitrogen-containing heterocycle.
[0024] In the solid electrolyte of this application, the nitrogen-containing heterocyclic cations in the nitrate ion liquid-based metal-organic framework bind the TFSI- anions in the lithium salt, while simultaneously promoting lithium salt dissociation to generate lithium fluoride in situ. Furthermore, nitrate ions gain electrons on the lithium metal anode surface and combine with lithium ions to form lithium nitride in situ within the SEI layer, thereby reducing dead lithium deposition and ultimately significantly improving the battery's interface stability. This high-quality SEI film can uniformly conduct Li... + This promotes uniform lithium deposition, thereby effectively suppressing the growth of lithium dendrites and greatly improving the safety and cycle life of lithium batteries.
[0025] Another aspect of this application proposes a method for preparing a solid electrolyte, used to prepare the solid electrolyte in the above-mentioned technical solution, comprising the following steps: S1. Add the nitrogen-containing heterocyclic compound and 1-chlorobutane to methanol, stir, remove methanol by rotary evaporation, and dry to obtain ionic liquid A; S2. Add ionic liquid A and sodium nitrate to methanol, stir, rotary evaporate, and dry to obtain nitrate ionic liquid B; S3. Add nitrate ionic liquid B and zinc acetate to methanol, stir, filter out the solid, wash and dry the solid to obtain porous, powdered nitrate ionic liquid-based metal-organic framework C. S4. Add nitrate ionic liquid-based metal-organic framework C and LiTFSI to acetonitrile and stir to obtain the first mixture; Polyethylene oxide is added to the first mixture and stirred to obtain the second mixture; The second mixture was dried to obtain a solid electrolyte containing nitrate ions in a liquid-based metal-organic framework.
[0026] One existing approach involves directly mixing and reacting a chloride-ion heterocyclic compound with zinc nitrate. Firstly, in this approach, Zn... 2+ NO3 - Cl - All coexist, undergoing complex competitive coordination and precipitation reactions, Zn 2+ It will preferentially coordinate with Cl, which has a stronger coordination ability. -The nitrogen atom in the heterocycle is effectively coordinated, forming ZnCl2 or Zn-Cl coordination units. The final products may include ZnCl2, nitrate ionic liquid B, and other compounds with amorphous coordination. Furthermore, the products contain a large amount of free NO3. - Cl - The incomplete separation of zinc nitrate results in numerous electrolyte impurities. While the electrolyte exhibits high ionic conductivity, it lacks a long-range ordered structure, affecting its ion transport mechanism, mechanical strength, and interfacial stability with the electrode. Secondly, zinc nitrate itself contains NO3... - Almost not with Zn 2+ It forms a stable coordination structure and cannot play a structure-guiding role; NO3 - It mainly exists as a free ion to balance the charge. Furthermore, NO3... - Lacking the ability to deprotonate, it cannot promote the formation of key (Zn and N) coordination bonds, which may lead to incomplete coordination or structural disorder.
[0027] In steps S1, S2, and S3 of this application, a relatively pure liquid-based metal-organic framework C containing nitrate ions is obtained. Firstly, the acetate ligand, of moderate strength, can react with Zn... 2+ Coordination plays a crucial role in the construction of secondary structural units in MOFs, contributing to the formation of specific and stable nuclei and frameworks. Its size and coordination mode influence the final channel shape. Secondly, it acts as a buffer and deprotonator in the reaction system, aiding in the deprotonation of highly acidic C2-H or other sites in heterocycles, thereby promoting better interaction between nitrogen atoms and Zn on the heterocycle. 2+ Coordination is key to forming stable Zn-N bonds.
[0028] Furthermore, the nitrogen-containing heterocyclic compounds include one or both of 6-bromo-4-hydro-imidazo[4,5-B]pyridine and 1H-imidazo[4,5-B]pyrazine.
[0029] Furthermore, in step S1, the molar ratio of the nitrogen heterocyclic compound to 1-chlorobutane is 1:1 to 1.1.
[0030] Furthermore, in step S2, the molar ratio of ionic liquid A to sodium nitrate is 1:1 to 1.1.
[0031] Furthermore, in step S3, the molar ratio of nitrate ionic liquid B to zinc acetate is 4:1.
[0032] Furthermore, in step S1, the mixture is stirred for 24 hours at a temperature of 55–70°C; the drying temperature is 60°C. In step S2, the mixture is stirred for 24 hours at a temperature of 50–65°C; the drying temperature is 60°C. In step S3, the mixture is stirred for 12 hours; the drying temperature is 80℃. Step S4: Stir for 2 hours when preparing the first mixture; The second mixture was stirred for 12 h, naturally dried for 2 h, and then vacuum dried for 24 h.
[0033] Another aspect of this application proposes a lithium battery comprising the solid electrolyte described in the above technical solution, or a solid electrolyte prepared by the solid electrolyte preparation method described in the above technical solution.
[0034] The following specific embodiments are further illustrations of this application. The examples given do not represent all the implementation methods of this application; only some are used as examples for illustration. Specific embodiments are as follows: Example 1 S1. At 55-70℃, 6-bromo-4-hydro-imidazo[4,5-B]pyridine (CAS:28279-49-4) and 1-chlorobutane were dissolved in 15 ml of methanol at a molar ratio of 1:1 to 1.1. The mixture was stirred and reacted for 24 hours. The methanol was removed by rotary evaporation, and the mixture was dried in a vacuum oven at 60℃ to obtain a yellow ionic liquid A.
[0035] The chemical formula of ionic liquid A is as follows: .
[0036] S2. At 50–65°C, ionic liquid A and sodium nitrate were dissolved in 15 ml of methanol at a molar ratio of 1:1.1 and stirred for 24 hours. The methanol was removed by rotary evaporation. After drying in a vacuum oven at 60°C, brownish-yellow nitrate ionic liquid B was obtained.
[0037] The chemical formula of nitrate ionic liquid B is as follows: .
[0038] S3. Dissolve nitrate ionic liquid B and zinc acetate in 20 ml methanol at a molar ratio of 4:1, and stir for 12 hours; then filter out the solid.
[0039] After washing the solid three times with methanol, it was dried in a vacuum oven at 80 °C to obtain a loose, porous, powdered nitrate ion liquid-based metal-organic framework C.
[0040] The chemical formula of the nitrate ion-based liquid-based metal-organic framework C is as follows: .
[0041] S4. The nitrate ion liquid-based metal-organic framework C and LiTFSI are added to acetonitrile and stirred for 2 h to obtain a first mixture; wherein the nitrate ion liquid-based metal-organic framework C accounts for 3 wt% of the polyethylene oxide.
[0042] The polyethylene oxide was added to the first mixture and stirred for 12 h until it was uniformly dispersed to obtain the second mixture; wherein the molar ratio of polyethylene oxide to LiTFSI was 10:1 and the mass ratio of polyethylene oxide to acetonitrile was 1:16.
[0043] The second mixture was poured into a mold and allowed to dry naturally for 2 hours, and then vacuum dried at 60°C for 24 hours to completely evaporate the residual solvent, thus obtaining a solid electrolyte containing nitrate ions in a liquid-based metal-organic framework.
[0044] Example 2 S1. At 55-70℃, 1H-imidazo[4,5-b]pyrazine and 1-chlorobutane were dissolved in 15ml of methanol at a molar ratio of 1:1-1.1. The mixture was stirred and reacted for 24 hours. The methanol was removed by rotary evaporation. After drying in a vacuum oven at 60℃, a yellow ionic liquid A was obtained.
[0045] The chemical formula of ionic liquid A is as follows: .
[0046] S2. At 50-65℃, ionic liquid A and sodium nitrate were dissolved in 15ml of methanol at a molar ratio of 1:1 and stirred for 24 hours. Methanol was removed by rotary evaporation. After drying in a vacuum oven at 60℃, brownish-yellow nitrate ionic liquid B was obtained.
[0047] The chemical formula of nitrate ionic liquid B is as follows: .
[0048] S3. Dissolve nitrate ionic liquid B and zinc acetate in 20 ml methanol at a molar ratio of 4:1, and stir for 12 hours; then filter out the solid.
[0049] After washing the solid with methanol 2-3 times, it was dried in a vacuum oven at 80 °C to obtain a loose, porous, powdered nitrate ion liquid-based metal-organic framework C.
[0050] The chemical formula of the nitrate ion-based liquid-based metal-organic framework C is as follows: .
[0051] S4. The nitrate ion liquid-based metal-organic framework C and LiTFSI are added to acetonitrile and stirred for 2 h to obtain a first mixture; wherein the nitrate ion liquid-based metal-organic framework C accounts for 3 wt% of the polyethylene oxide.
[0052] The polyethylene oxide was added to the first mixture and stirred for 12 h until it was uniformly dispersed to obtain the second mixture; wherein the molar ratio of polyethylene oxide to LiTFSI was 10:1 and the mass ratio of polyethylene oxide to acetonitrile was 1:16.
[0053] The second mixture was poured into a mold and allowed to dry naturally for 2 hours, and then vacuum dried at 60°C for 24 hours to completely evaporate the residual solvent, thus obtaining a solid electrolyte containing nitrate ions in a liquid-based metal-organic framework.
[0054] Comparative Example 1 LiTFSI was added to acetonitrile and stirred for 2 h to obtain a first mixture. Ethylene oxide was added to the first mixture and stirred for 12 h until uniformly dispersed to obtain a second mixture; wherein the molar ratio of polyethylene oxide to LiTFSI was 10:1, and the mass ratio of polyethylene oxide to acetonitrile was 1:16. The second mixture was poured into a mold and allowed to dry naturally for 2 h, then vacuum dried at 60 °C for 24 h to completely evaporate the residual solvent, yielding a nitrate-free liquid-based metal-organic framework solid electrolyte.
[0055] The solid electrolyte prepared in Example 1 and Comparative Example 1 were subjected to performance tests in this application. Figure 1 The solid electrolytes in Example 1 and Comparative Example 1 were used to assemble coin cells with two inert stainless steel (SS) electrodes to test their ionic conductivity. Figure 1 It can be seen that the electrolyte with a nitrate ion-based liquid metal-organic framework in Example 1 has a conductivity of 2.55 × 10⁻⁶. -4 The S / cm ratio is significantly higher than that of the electrolyte in Comparative Example 1, which does not contain nitrate ions and is based on a liquid metal-organic framework (4.7 × 10⁻⁶). -5 S / cm indicates that electrolytes containing nitrate ions in liquid-based metal-organic frameworks have higher ion mobility compared to electrolytes without nitrate ions in liquid-based metal-organic frameworks.
[0056] Figure 2 The solid electrolytes of Example 1 and Comparative Example 1 were used to assemble lithium-ion symmetric batteries, and the lithium-ion transference numbers were tested on an electrochemical workstation (using the impedance before and after polarization and the current before and after polarization in the it test). Figure 2 It can be seen that the lithium-ion transference number of the electrolyte containing a nitrate ion liquid-based metal-organic framework in Example 1 is 0.5, which is much higher than that of the electrolyte in Comparative Example 2, which does not contain a nitrate ion liquid-based metal-organic framework, at 0.18. This indicates that the electrolyte containing a nitrate ion liquid-based metal-organic framework has a higher lithium-ion migration capacity than the electrolyte without a nitrate ion liquid-based metal-organic framework.
[0057] Figure 3 The critical current density of lithium-ion symmetric batteries assembled with solid electrolytes from Example 1 and the comparative example was tested. Figure 3 It can be seen that the critical current density of the electrolyte containing nitrate ions in Example 1, based on a liquid metal-organic framework, is 1.29 mA / cm². -2 This is significantly higher than the 0.58 mA / cm² of the electrolyte in Comparative Example 1, which is a liquid-based metal-organic framework electrolyte that does not contain nitrate ions. -2 This indicates that electrolytes containing nitrate ions in liquid-based metal-organic frameworks have higher lithium dendrite suppression and current carrying capacity compared to electrolytes without nitrate ions in liquid-based metal-organic frameworks.
[0058] Figure 4 The solid electrolytes of Example 1 and Comparative Example 1 were used to assemble lithium-ion symmetric batteries, and their cycle performance was tested. Figure 4 It can be seen that the electrolyte containing nitrate ions in Example 1 has a stable cycling time of 2800 h, which is much higher than the 480 h of the electrolyte without nitrate ions in Comparative Example 1. The electrolyte containing nitrate ions exhibits higher lithium metal battery interface stability compared to the electrolyte without nitrate ions.
[0059] Figure 5 The solid electrolytes of Example 1 and Comparative Example 1 were used to assemble coin cells with lithium iron phosphate cathodes and lithium anodes, respectively, and the cycle stability of the cells was tested. Figure 5 It can be seen that the electrolyte containing nitrate ions in Example 1, a liquid-based metal-organic framework, exhibits stable cycling stability for over 1000 cycles, significantly higher than the 200 cycles achieved by the electrolyte in Comparative Example 1, which does not contain nitrate ions. This indicates that the electrolyte containing nitrate ions exhibits better cycling stability compared to the electrolyte without nitrate ions.
[0060] Figure 6 This is the XPS spectrum of the lithium-symmetric battery assembled in the solid electrolyte of Example 1 after 50 hours of cycling. Analysis of the carbon (C), lithium (Li), fluorine (F), and nitrogen (N) spectra at the interface between the lithium anode and the electrolyte, which contains a liquid-based metal-organic framework with nitrate ions, demonstrates the successful construction of lithium nitride and lithium fluoride components.
[0061] Figure 7 The solid electrolytes of Example 2 and Comparative Example 2 were used to assemble coin cells with two inert stainless steel (SS) electrodes to test their ionic conductivity. Figure 7 It can be seen that the electrolyte conductivity of the nitrate ion-containing liquid-based metal-organic framework in Example 2 is 2.82 × 10⁻⁶.-4 The S / cm ratio is significantly higher than that of the 4.7 × 10⁻⁶ of the electrolyte in Comparative Example 1, which is a liquid-based metal-organic framework electrolyte that does not contain nitrate ions. -5 S / cm indicates that electrolytes containing nitrate ions in liquid-based metal-organic frameworks have higher ion mobility compared to electrolytes without nitrate ions in liquid-based metal-organic frameworks.
[0062] Figure 8 The solid electrolytes of Example 2 and Comparative Example 1 were used to assemble lithium-ion symmetric batteries, and the lithium-ion transference numbers were tested on an electrochemical workstation (using the impedance before and after polarization and the current before and after polarization in the it test). Figure 8 It can be seen that the lithium-ion transference number of the electrolyte containing a nitrate ion liquid-based metal-organic framework in Example 2 is 0.56, which is much higher than the 0.18 of the electrolyte in Comparative Example 1 that does not contain a nitrate ion liquid-based metal-organic framework. This indicates that the electrolyte containing a nitrate ion liquid-based metal-organic framework has a higher lithium-ion migration capacity than the electrolyte that does not contain a nitrate ion liquid-based metal-organic framework.
[0063] Figure 9 Lithium-ion symmetric batteries were assembled in Example 2 and Comparative Example 1, and their cycle performance was tested. The electrolyte in Example 2, containing a nitrate ion liquid-based metal-organic framework, had a stable cycle time of 1200 hours, which was significantly longer than the 480 hours of the electrolyte in Comparative Example 1, which did not contain a nitrate ion liquid-based metal-organic framework. The electrolyte containing the nitrate ion liquid-based metal-organic framework exhibits higher lithium metal battery interface stability compared to the electrolyte without the nitrate ion liquid-based metal-organic framework.
[0064] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this application and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this application should be included within the protection scope of this application. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.
Claims
1. A solid electrolyte, characterized in that, The composition includes a nitrate ionic liquid-based metal-organic framework C, polyethylene oxide, and LiTFSI, wherein the nitrate ionic liquid-based metal-organic framework C accounts for 3 wt% of the polyethylene oxide, and the molar ratio of the polyethylene oxide to LiTFSI is 10:1; wherein, The nitrate ion liquid-based metal-organic framework C has a nitrogen-containing heterocycle, on which nitrate ions and Zn ions are coordinated.
2. A method for preparing a solid electrolyte, used to prepare the solid electrolyte of claim 1, characterized in that, S1. Add the nitrogen-containing heterocyclic compound and 1-chlorobutane to methanol, stir, remove methanol by rotary evaporation, and dry to obtain ionic liquid A; S2. Add the ionic liquid A and sodium nitrate to methanol, stir, rotary evaporate, and dry to obtain nitrate ionic liquid B; S3. Add the nitrate ionic liquid B and zinc acetate to methanol, stir, filter out the solid, wash and dry the solid to obtain a porous, powdered nitrate ionic liquid-based metal-organic framework C. S4. Add the nitrate ionic liquid-based metal-organic framework C and LiTFSI to acetonitrile and stir to obtain the first mixture; Polyethylene oxide is added to the first mixture and stirred to obtain the second mixture; The second mixture was dried to obtain a solid electrolyte containing a liquid-based metal-organic framework of nitrate ions.
3. The method for preparing a solid electrolyte according to claim 2, characterized in that, The nitrogen-containing heterocyclic compound includes one or both of 6-bromo-4-hydro-imidazo[4,5-B]pyridine and 1H-imidazo[4,5-B]pyrazine.
4. The method for preparing a solid electrolyte according to claim 3, characterized in that, In step S1, the molar ratio of the nitrogen heterocyclic compound to 1-chlorobutane is 1:1 to 1.
1.
5. The method for preparing a solid electrolyte according to claim 3, characterized in that, In step S2, the molar ratio of ionic liquid A to sodium nitrate is 1:1 to 1.
1.
6. The method for preparing a solid electrolyte according to claim 3, characterized in that, In step S3, the molar ratio of the nitrate ionic liquid B to zinc acetate is 4:
1.
7. The method for preparing a solid electrolyte according to claim 3, characterized in that, In step S1, the mixture is stirred for 24 hours at a temperature of 55–70°C; the drying temperature is 60°C. In step S2, the mixture is stirred for 24 hours at a temperature of 50–65°C; the drying temperature is 60°C. In step S3, the mixture is stirred for 12 hours; the drying temperature is 80℃. Step S4: Stir for 2 hours when preparing the first mixture; The second mixture was stirred for 12 h, naturally dried for 2 h, and then vacuum dried for 24 h.
8. A lithium battery, characterized in that, The solid electrolyte comprises the solid electrolyte as described in claim 1, or the solid electrolyte prepared by any one of the solid electrolyte preparation methods of claims 2-7.