Amide electrolyte, preparation method and sodium battery
By using an amide electrolyte composed of fluoroethylene carbonate and amide solvent, the compatibility problem between the electrolyte and the sodium metal anode and high-voltage cathode in sodium batteries was solved, forming a stable SEI layer and improving the cycle stability and high-voltage performance of sodium batteries.
Patent Information
- Application Number
- CN202511886785.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-02-13
AI Technical Summary
There is a thermodynamic mismatch between traditional carbonate-based electrolytes and sodium metal anodes and high-voltage cathodes, which leads to dendrite growth, interfacial side reactions, poor oxidation stability, and insufficient compatibility, resulting in short cycle life, low coulombic efficiency, and high safety risks in sodium batteries.
A composite solvent consisting of fluoroethylene carbonate and amide solvent is used, and sodium salt is added to form an amide electrolyte. By forming a NaF-rich solid electrolyte interphase (SEI) layer on the sodium anode surface, the interfacial mechanical stability and oxidation stability are improved.
Significantly improves the reversibility and cycle life of sodium batteries, enhances cycle performance and rate performance under high voltage, improves coulombic efficiency, and extends cycle life.
Smart Images
Figure CN121529014A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery electrolyte technology, and more particularly to an amide electrolyte, its preparation method, and a sodium battery. Background Technology
[0002] Sodium batteries have been extensively researched by governments and enterprises due to the abundance and uniform distribution of their raw materials. Sodium metal anodes (SMAs) possess an extremely high theoretical specific capacity (1166 mAh g⁻¹). -1 With its low redox potential (-2.71 V vs. SHE), and if matched with a high-voltage cathode to assemble high-voltage sodium metal batteries (SMBs), their energy density is expected to surpass that of existing lithium iron phosphate-based lithium-ion batteries. In this battery system, the electrolyte, as the "blood" of the battery, plays a crucial role in ion transport and has a decisive impact on the overall battery performance. However, there is a thermodynamic mismatch between traditional carbonate-based electrolytes and highly active SMAs, which easily induces a series of serious problems such as dendrite growth, interfacial side reactions, and uncontrolled gas generation, resulting in extremely low Na deposition / stripping reversibility and short cycle life. On the other hand, this type of electrolyte has poor oxidation stability and insufficient interfacial compatibility, leading to rapid electrolyte consumption, cathode structure collapse, and interfacial damage under high-voltage conditions, which in turn causes rapid capacity decay, shortened cycle life, decreased coulombic efficiency, and increased safety risks. For this reason, the traditional carbonate-based electrolyte system struggles to achieve a synergy between high-voltage cathode stability and SMA compatibility, which has become a bottleneck restricting the practical application of high-energy-density SMBs.
[0003] To address the challenge of poor compatibility between electrolytes and Na anodes and high-voltage cathodes, researchers have proposed various modification strategies, such as using ether-based electrolytes, fluorinated cosolvents / perfluorinated carbonate electrolytes, high-concentration / locally high-concentration electrolytes, and introducing functional electrolyte additives, achieving significant results. These strategies all revolve around "interface regulation" and "electrolyte stability enhancement." Although ether-based electrolytes exhibit extremely high compatibility with Na anodes, their poor oxidative stability (<4.0 V) limits their development in high-voltage systems. Introducing fluorinated carbonate cosolvents, perfluorinated carbonate electrolytes, or fluorinated electrolyte additives can preferentially reduce Na on the Na anode surface, forming a NaF-rich SEI, improving the mechanical stability, electronic insulation, and thermal stability of the interface. However, the low ionic conductivity and limited interfacial stability of NaF result in generally low Na deposition / stripping coulombic efficiencies (<98%) and short cycle lives for these fluorinated carbonate-based electrolytes. Furthermore, high-concentration electrolytes often suffer from problems such as high viscosity, decreased ionic conductivity, and increased costs due to their excessively high salt content. Therefore, developing other novel electrolyte systems to achieve efficient and stable control of the electrode / electrolyte interface is crucial for advancing high-energy-density batteries from the laboratory to engineering applications. Summary of the Invention
[0004] The purpose of this invention is to provide an amide electrolyte, a preparation method, and a sodium battery, which solves the problems of poor reversibility and cycle stability, as well as poor cycle performance and rate performance under high voltage in existing sodium batteries.
[0005] To achieve the above objectives, the present invention provides an amide electrolyte comprising a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, the volume ratio of fluoroethylene carbonate to the amide solvent is 1:1-5, and the molar concentration of the sodium salt is 0.8M-1.2M.
[0006] Preferably, the volume ratio of the fluoroethylene carbonate to the amide solvent is 1:4.
[0007] Preferably, the amide solvent includes at least one selected from N,N-diethylacetamide, N,N-diethyl-2,2,2-trifluoroacetamide, N,N-dimethyltrifluoroacetamide, and N-methoxy-N-methyl-2,2,2-trifluoroacetamide.
[0008] Preferably, the molar concentration of the sodium salt is 1M.
[0009] Preferably, the sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
[0010] The preparation method of the above-mentioned amide electrolyte includes the following steps: S1. Fluoroethylene carbonate and amide solvent are mixed in a glove box to obtain a mixed solvent; S2. Add sodium salt to the mixed solvent and stir evenly at room temperature to obtain electrolyte.
[0011] Preferably, in S1, the volume ratio of fluoroethylene carbonate to amide solvent is 1:4, and the amide solvent is N,N-diethylacetamide, N,N-diethyl-2,2,2-trifluoroacetamide, N,N-dimethyltrifluoroacetamide, or N-methoxy-N-methyl-2,2,2-trifluoroacetamide.
[0012] Preferably, in S2, the molar concentration of the sodium salt is 1M, and the sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
[0013] A sodium battery includes the aforementioned amide electrolyte, a positive electrode, a negative electrode, and a separator, wherein the positive electrode is metallic sodium, metallic copper, or NaNi. x Fe y Mn z O2, with metallic sodium as the negative electrode and glass fiber as the diaphragm.
[0014] Preferably, the positive and negative electrodes of the sodium battery are both symmetrical cells of metallic sodium; the positive electrode of the sodium battery is metallic copper or NaNi. x Fe y Mn z O2, the negative electrode is a half-cell of metallic sodium.
[0015] The advantages and positive effects of the amide electrolyte, preparation method, and sodium battery described in this invention are as follows: The electrolyte in this invention uses a perfluorinated solvent, which promotes the decomposition of the Na anode surface to form a NaF-rich SEI, improving the mechanical stability of the interface and enhancing the reversibility and cycle life of the battery. The fluorinated solvent has higher oxidation stability, which is beneficial for improving the cycle performance and rate performance of the sodium battery under high voltage.
[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0017] Figure 1 The performance of the Na‖Na symmetric cells assembled in Examples 1-2 and Comparative Example 1 of this invention; Figure 2 The cycle performance of the Na‖Cu half-cells assembled in Examples 1-2 and Comparative Example 1 of this invention is shown. Figure 3 The average coulombic efficiency of the Na‖Cu half-cell assembled in Examples 1-2 and Comparative Example 1 of this invention; Figure 4The cycle performance of the Na‖Cu half-cells assembled in Examples 2-4 of this invention; Figure 5 The cycle performance of the Na‖Cu half-cells assembled in Examples 2, 5, and 6 of this invention; Figure 6 The cycle performance of the Na‖NFM batteries assembled in Examples 1-2 and Comparative Example 1 of this invention; Figure 7 The rate performance of the Na‖NFM batteries assembled in Examples 1-2 and Comparative Example 1 of this invention is shown. Detailed Implementation
[0018] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.
[0019] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.
[0020] An amide electrolyte comprising a sodium salt and a composite solvent, the composite solvent comprising fluoroethylene carbonate and an amide solvent, wherein the volume ratio of fluoroethylene carbonate to the amide solvent is 1:1-5, and the molar concentration of the sodium salt is 0.8M-1.2M.
[0021] The preferred volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0022] The amide solvent includes at least one of N,N-diethylacetamide, N,N-diethyl-2,2,2-trifluoroacetamide, N,N-dimethyltrifluoroacetamide, and N-methoxy-N-methyl-2,2,2-trifluoroacetamide.
[0023] The structural formula of N,N-diethylacetamide is: .
[0024] The structural formula of N,N-diethyl-2,2,2-trifluoroacetamide is: .
[0025] The structural formula of N,N-dimethyltrifluoroacetamide is: .
[0026] The structural formula of N-methoxy-N-methyl-2,2,2-trifluoroacetamide is: .
[0027] The preferred molar concentration of the sodium salt is 1 M.
[0028] The sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
[0029] The preparation method of amide electrolyte includes the following steps: S1. Fluoroethylene carbonate and amide solvent are mixed in a glove box to obtain a mixed solvent.
[0030] The volume ratio of fluoroethylene carbonate to amide solvent is 1:4, and the amide solvent is N,N-diethylacetamide or N,N-diethyl-2,2,2-trifluoroacetamide.
[0031] S2. Add sodium salt to the mixed solvent and stir evenly at room temperature to obtain electrolyte.
[0032] The molar concentration of the sodium salt is 1M, and the sodium salt includes one of sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
[0033] A sodium battery includes the aforementioned amide electrolyte, a positive electrode, a negative electrode, and a separator, wherein both the positive and negative electrodes are metallic sodium.
[0034] The positive electrode is metallic sodium, metallic copper, or NaNi. x Fe y Mn z O2, with metallic sodium as the negative electrode and glass fiber as the diaphragm.
[0035] Example 1 The amide electrolyte comprises a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, and the volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0036] The sodium salt is sodium bis(fluorosulfonyl)imide (NaFSI), and the molar concentration of the sodium salt is 1M.
[0037] The amide solvent is N,N-diethylacetamide (DTM).
[0038] The preparation method of amide electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), fluoroethylene carbonate (FEC) and N,N-diethylacetamide are mixed at a volume ratio of 1:4 to obtain a mixed solvent.
[0039] S2. Add sodium bis(fluorosulfonyl)imide with a molar concentration of 1M to the mixed solvent, and stir evenly at room temperature to obtain NaFSI-FEC / DTM electrolyte.
[0040] Example 2 The amide electrolyte comprises a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, and the volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0041] The sodium salt is sodium bis(fluorosulfonyl)imide (NaFSI), and the molar concentration of the sodium salt is 1M.
[0042] The amide solvent is N,N-diethyl-2,2,2-trifluoroacetamide (DTFM).
[0043] The preparation method of amide electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), fluoroethylene carbonate (FEC) and N,N-diethyl-2,2,2-trifluoroacetamide are mixed at a volume ratio of 1:4 to obtain a mixed solvent.
[0044] S2. Add sodium bis(fluorosulfonyl)imide with a molar concentration of 1M to the mixed solvent, and stir evenly at room temperature to obtain NaFSI-FEC / DTFM electrolyte.
[0045] Example 3 The amide electrolyte comprises a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, and the volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0046] The sodium salt is sodium bis(fluorosulfonyl)imide (NaFSI), and the molar concentration of the sodium salt is 1M.
[0047] The amide solvent is N,N-dimethyltrifluoroacetamide (FDMA).
[0048] The preparation method of amide electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), fluoroethylene carbonate (FEC) and N,N-dimethyltrifluoroacetamide are mixed at a volume ratio of 1:4 to obtain a mixed solvent.
[0049] S2. Add sodium bis(fluorosulfonyl)imide with a molar concentration of 1M to the mixed solvent, and stir evenly at room temperature to obtain NaFSI-FEC / FDMA electrolyte.
[0050] Example 4 The amide electrolyte comprises a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, and the volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0051] The sodium salt is sodium bis(fluorosulfonyl)imide (NaFSI), and the molar concentration of the sodium salt is 1M.
[0052] The amide solvent is N-methoxy-N-methyl-2,2,2-trifluoroacetamide (FMMA).
[0053] The preparation method of amide electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), fluoroethylene carbonate (FEC) and N-methoxy-N-methyl-2,2,2-trifluoroacetamide are mixed at a volume ratio of 1:4 to obtain a mixed solvent.
[0054] S2. Add sodium bis(fluorosulfonyl)imide with a molar concentration of 1M to the mixed solvent, and stir evenly at room temperature to obtain NaFSI-FEC / FMMA electrolyte.
[0055] Example 5 The amide electrolyte comprises a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, and the volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0056] The sodium salt is sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), and the molar concentration of the sodium salt is 1M.
[0057] The amide solvent is N,N-diethyl-2,2,2-trifluoroacetamide (DTFM).
[0058] The preparation method of amide electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), fluoroethylene carbonate (FEC) and N,N-diethyl-2,2,2-trifluoroacetamide are mixed at a volume ratio of 1:4 to obtain a mixed solvent.
[0059] S2. Add sodium bis(trifluoromethanesulfonyl)imide with a molar concentration of 1M to the mixed solvent, and stir evenly at room temperature to obtain NaTFSI-FEC / DTFM electrolyte.
[0060] Example 6 The amide electrolyte comprises a sodium salt and a composite solvent, wherein the composite solvent comprises fluoroethylene carbonate and an amide solvent, and the volume ratio of fluoroethylene carbonate to amide solvent is 1:4.
[0061] The sodium salt is sodium hexafluorophosphate (NaPF6), and the molar concentration of the sodium salt is 1M.
[0062] The amide solvent is N,N-diethyl-2,2,2-trifluoroacetamide (DTFM).
[0063] The preparation method of amide electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), fluoroethylene carbonate (FEC) and N,N-diethyl-2,2,2-trifluoroacetamide are mixed at a volume ratio of 1:4 to obtain a mixed solvent.
[0064] S2. Add 1M sodium hexafluorophosphate to the mixed solvent and stir evenly at room temperature to obtain NaPF6-FEC / DTFM electrolyte.
[0065] Comparative Example 1 The electrolyte consists of a sodium salt and a composite solvent, which consists of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1:1.
[0066] The sodium salt is sodium hexafluorophosphate (NaPF6), and the molar concentration of the sodium salt is 1M.
[0067] The preparation method of this electrolyte includes the following steps: S1. In a glove box (H2O<0.1 ppm, O2<0.1 ppm), ethylene carbonate (EC) and diethyl carbonate are mixed at a volume ratio of 1:1 to obtain a mixed solvent.
[0068] S2. Add 1M sodium hexafluorophosphate to the mixed solvent and stir until homogeneous at room temperature to obtain NaPF6-EC / DEC electrolyte. Assemble the electrolytes prepared in Examples 1-6 and Comparative Example 1 into symmetrical cells and half-cells, respectively, and perform performance tests.
[0069] The symmetric cell was fabricated as follows: Cut sheet-like metallic sodium was used as the positive and negative electrodes, respectively, and glass fiber was used as the separator to assemble a Na‖Na symmetric cell. A constant current deposition / stripping test was performed using the Xinwei Battery Testing System. The charge / discharge current density was 1 mA cm⁻¹. -2 The surface capacity is 1 mAh cm -2 .
[0070] The preparation method of the Na‖Cu half-cell is as follows: Cut sodium metal sheets are used as the negative electrode, copper foil as the positive electrode, and glass fiber is used as the separator. The Na‖Cu half-cell is assembled, and Na deposition / stripping tests are performed using the Xinwei Battery Testing System. During cycle performance testing, the charge / discharge current density is 1 mA cm⁻¹. -2 The surface capacity is 2 mAh cm -2 During the average coulombic efficiency test, the charge / discharge current density was 1 mA cm⁻¹. -2 The surface capacity is 1 mAh cm -2 .
[0071] The preparation method of Na‖NFM battery is as follows: sodium metal is used as the negative electrode, NaNi x Fe y Mn z O2(NFM) was used as the positive electrode to assemble a Na‖NFM battery, and constant current charge and discharge tests were performed using the Xinwei Battery Testing System.
[0072] Figure 1 The performance of the Na‖Na symmetric cells assembled in Examples 1-2 and Comparative Example 1 of this invention is shown. Figure 1 As shown, the symmetric battery assembled using the electrolyte of Comparative Example 1 exhibited rapid polarization after 50 hours of cycling, while the Na‖Na symmetric batteries in Examples 1 and 2 showed significant improvement. The symmetric battery in Example 2 did not show obvious polarization after 600 hours, and its performance was more than 12 times better than that of the electrolyte in Comparative Example 1.
[0073] Figure 2 The cycling performance of the Na‖Cu half-cells assembled in Examples 1-2 and Comparative Example 1 of this invention is shown. Figure 3 The average coulombic efficiency of the Na‖Cu half-cells assembled in Examples 1-2 and Comparative Example 1 of this invention is given. Figure 4 The cycling performance of the Na‖Cu half-cells assembled in Examples 2-4 of this invention is shown. Figure 2 , Figure 3 , Figure 4 The Na deposition / stripping efficiencies in Comparative Example 1, Example 1, and Example 2 are shown respectively. Compared to conventional carbonate electrolytes, amide-based electrolytes exhibit excellent coulombic efficiency in Na‖Cu half-cell performance, especially the electrolyte in Example 2, which has a cycle life of over 150 cycles and an average coulombic efficiency of up to 99.02%.
[0074] Figure 5 The cycling performance of the Na‖Cu half-cells assembled in Examples 2, 5, and 6 of this invention is shown. Figure 5 As shown, different electrolyte salts have a significant impact on battery performance. Overall, NaFSI is the best performing electrolyte salt.
[0075] Figure 6 The cycling performance of the Na‖NFM batteries assembled in Examples 1-2 and Comparative Example 1 of this invention is shown. Figure 6 As shown, the electrolyte in Example 2 exhibits significantly better cycle stability than the electrolytes in Comparative Example 1 and Example 1. After 200 cycles, the Na‖NFM battery in Example 2 retains 91.6% of its capacity, with an average coulombic efficiency as high as 99.6%. In contrast, the Na‖NFM battery in Comparative Example 1 only retains 74.4% of its capacity after 100 cycles, and its coulombic efficiency fluctuates significantly, indicating severe oxidative decomposition of the surface electrolyte under high voltage.
[0076] Figure 7 The rate performance of the Na‖NFM batteries assembled in Examples 1-2 and Comparative Example 1 of this invention is shown. Figure 7 As shown, the Na‖NFM battery of Example 2 has significantly higher cycle rate performance than Comparative Example 1 and Example 1, especially at a current density of 5C, where the capacity remains at 64% of the original specific capacity, indicating faster ion transport kinetics.
[0077] In summary, the electrolyte described in this invention can significantly improve the cycle stability and coulombic efficiency of the sodium anode, with the electrolyte in Example 2 exhibiting even better performance. The perfluorinated solvent of the amide electrolyte has a lower least unoccupied molecular orbital (LUMO) energy level, which can preferentially decompose on the Na anode surface to form a NaF-rich SEI, improving the mechanical stability of the interface and enhancing the reversibility and cycle life of the battery. Secondly, the fluorinated solvent has higher oxidation stability, supporting the normal operation of the high-voltage (≥4.2 V) cathode; furthermore, FEC and DTFM solvents have weaker solvation capabilities, and in Example 2, the FEC and DTFM solvents react with Na... + The coordination effect is the weakest, which can promote Na to a greater extent. + It desolvates the structure and inhibits solvent decomposition. Furthermore, it enhances FSI. - Anions and Na + The coordination number promotes anion reduction, forming an inorganic-rich SEI, which improves the mechanical stability and ionic conductivity of the interface. Ultimately, Example 2 achieved the highest coulombic efficiency, the longest cycle life, and the best rate performance.
[0078] Therefore, by using the amide electrolyte, preparation method, and sodium battery described in this invention, the problems of poor reversibility and cycle stability, as well as poor cycle performance and rate performance under high voltage, of existing sodium batteries can be solved.
[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. An amide electrolyte, characterized in that: It includes sodium salt and a composite solvent, the composite solvent including fluoroethylene carbonate and amide solvent, the volume ratio of fluoroethylene carbonate to amide solvent is 1:1-5, and the molar concentration of sodium salt is 0.8M-1.2M.
2. The amide electrolyte according to claim 1, characterized in that: The volume ratio of the fluoroethylene carbonate to the amide solvent is 1:
4.
3. The amide electrolyte according to claim 1, characterized in that: The amide solvent includes at least one of N,N-diethylacetamide, N,N-diethyl-2,2,2-trifluoroacetamide, N,N-dimethyltrifluoroacetamide, and N-methoxy-N-methyl-2,2,2-trifluoroacetamide.
4. The amide electrolyte according to claim 1, characterized in that: The molar concentration of the sodium salt is 1M.
5. The amide electrolyte according to claim 1, characterized in that: The sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
6. A method for preparing an amide electrolyte according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Fluoroethylene carbonate and amide solvent are mixed in a glove box to obtain a mixed solvent; S2. Add sodium salt to the mixed solvent and stir evenly at room temperature to obtain electrolyte.
7. A method for preparing the amide electrolyte according to claim 6, characterized in that: In S1, the volume ratio of fluoroethylene carbonate to amide solvent is 1:4, and the amide solvent is N,N-diethylacetamide, N,N-diethyl-2,2,2-trifluoroacetamide, N,N-dimethyltrifluoroacetamide, or N-methoxy-N-methyl-2,2,2-trifluoroacetamide.
8. A method for preparing the amide electrolyte according to claim 6, characterized in that: In S2, the molar concentration of the sodium salt is 1M, and the sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
9. A sodium battery, characterized in that: Includes the amide electrolyte, positive electrode, negative electrode, and separator as described in any one of claims 1-5, wherein the positive electrode is metallic sodium, metallic copper, or NaNi. x Fe y Mn z O2, with metallic sodium as the negative electrode and glass fiber as the diaphragm.
10. A sodium battery according to claim 9, characterized in that: The sodium battery is a symmetrical cell where both the positive and negative electrodes are metallic sodium; the positive electrode is metallic copper or NaNi. x Fe y Mn z O2, the negative electrode is a half-cell of metallic sodium.