Ether electrolyte and sodium-copper battery

Abstract

The invention relates to the technical field of sodium metal batteries, in particular to an ether electrolyte and a sodium-copper battery, and the ether electrolyte comprises sodium salt and an organic solvent; the organic solvent is composed of an ether organic solvent and an ester organic solvent. The ester organic solvent is added into the ether electrolyte of the sodium-copper battery, and the ester organic solvent is decomposed to form a gradient solid electrolyte interface film to inhibit dendritic crystal growth on the surface of sodium, so that the overpotential of sodium deposition is remarkably reduced; moreover, the ether electrolyte is matched with a diaphragm in the sodium-copper battery, so that shuttling of copper ions from a positive electrode to a negative electrode can be effectively inhibited, coulombic efficiency can be effectively improved, and good cycling stability can be kept.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium metal batteries, in particular to an ether electrolyte and a sodium-copper battery. Background Art

[0002] In traditional battery systems, metals are often used as the negative electrode of the battery. However, there have been reports recently on the use of metals as positive electrodes. Among them, copper can be used as a high-capacity positive electrode in addition to the negative electrode. During the deposition / stripping process of the positive electrode copper, the copper foil is exposed to the Na / Na + It exhibits reversible redox behavior within a potential window of approximately 3V (oxidizing to copper ions during charging and reducing to metallic copper during discharge), making it suitable for direct use as the positive electrode material for sodium metal batteries. Directly using copper sheets as the positive electrode not only reduces costs but also simplifies the battery assembly process.

[0003] By matching organic electrolytes in copper foil and sodium foil, a room temperature sodium-copper battery system can be constructed. This battery relies on Cu / Cu + andNa / Na + Two independent electrochemical oxidation / reduction reactions reversibly store and release electrical energy. The key challenge restricting the practical application of sodium-copper batteries is how to effectively inhibit the uncontrollable migration of copper ions from the positive electrode to the metallic sodium negative electrode (i.e., the "copper shuttle effect"). The dendrite growth and capacity decay caused by this process will seriously affect the battery cycle stability. Therefore, in order to inhibit the shuttle diffusion of copper ions in the sodium-copper bimetallic deposition-dissolution reversible battery energy storage process, a new electrolyte system needs to be developed through electrolyte engineering. However, the existing electrolyte cannot inhibit the dendrite growth on the surface of sodium foil and is expensive.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an ether electrolyte and a sodium-copper battery, aiming to solve the problem that the existing electrolyte cannot inhibit the dendrite growth on the surface of sodium foil and is expensive.

[0006] The technical solutions of the present invention are as follows:

[0007] An ether electrolyte comprises sodium salt and an organic solvent; the organic solvent is composed of an ether organic solvent and an ester organic solvent.

[0008] In the ether electrolyte, the ester organic solvent includes one or more of ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.

[0009] The ether electrolyte, wherein the ether organic solvent includes one or more of tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0010] The ether electrolyte, wherein the volume ratio of the ether organic solvent to the ester organic solvent is (5-8):(2-4).

[0011] In the ether electrolyte, the volume ratio of the ether organic solvent to the ester organic solvent is 7:3.

[0012] The ether electrolyte, wherein the sodium salt includes one or more of sodium bis(trifluoromethylsulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium hexafluorophosphate, sodium perchlorate, sodium bis(oxalatoborate), sodium tetrafluoroborate, sodium hexafluoroarsenate, and sodium trifluoromethylsulfonate.

[0013] The ether electrolyte, wherein the concentration of the sodium salt in the ether electrolyte is 0.1 mol / L-5 mol / L.

[0014] The ether electrolyte, wherein the ether organic solvent is tetrahydrofuran; the ester organic solvent is fluoroethylene carbonate.

[0015] A sodium-copper battery comprises a sodium negative electrode, a copper positive electrode, a separator arranged between the sodium negative electrode and the copper negative electrode, and an ether electrolyte for immersing the sodium negative electrode and the copper positive electrode.

[0016] In the sodium-copper battery, the diaphragm is composed of a composite film of polypropylene and polyimide and glass fiber membranes arranged on both sides of the composite film.

[0017] Beneficial Effects: The present invention provides an ether electrolyte and a sodium-copper battery. The ether electrolyte comprises a sodium salt and an organic solvent; the organic solvent comprises an ether organic solvent and an ester organic solvent. The present invention adds an ester organic solvent to the ether electrolyte of the sodium-copper battery, utilizing the decomposition of the ester organic solvent to form a gradient solid electrolyte interface (SEI) film to inhibit dendrite growth on the sodium surface, thereby significantly reducing the overpotential for sodium deposition. Furthermore, combining the ether electrolyte with the separator in the sodium-copper battery effectively inhibits the shuttling of copper ions from the positive electrode to the negative electrode, effectively improving coulombic efficiency and maintaining good cycle stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a quantitative relationship diagram between mass change and the amount of electricity consumed during the electrode reaction;

[0019] Figure 2 Schematic diagram of the layer structure of sodium-copper battery;

[0020] Figure 3 The sodium-copper battery assembled with the electrolyte prepared in Example 1 was -2 and 1mAh cm -2 Cycle performance curve diagram;

[0021] Figure 4 The SEM images of the positive electrode copper foam before and after cycling in Example 1;

[0022] Figure 5 This is the XRD pattern of the positive electrode copper foam after charging and discharging in Example 1. DETAILED DESCRIPTION

[0023] The present invention provides an ether electrolyte and a sodium-copper battery. To clarify the objectives, technical solutions, and effects of the present invention, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0024] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0025] The invention provides an ether electrolyte comprising sodium salt and an organic solvent; the organic solvent consists of an ether organic solvent and an ester organic solvent.

[0026] In this embodiment, an ester organic solvent is added to the ether electrolyte of the sodium-copper battery, and the ester organic solvent is decomposed to form a gradient solid electrolyte interface (SEI) film to inhibit the growth of dendrites on the sodium surface, thereby significantly reducing the overpotential of sodium deposition; and the ether electrolyte is combined with the separator in the sodium-copper battery to effectively inhibit the shuttling of copper ions from the positive electrode to the negative electrode, which can effectively improve the coulombic efficiency and maintain good cycle stability.

[0027] Specifically, the present invention utilizes the property of the ether organic solvent and the ester organic solvent to form a solvation with the sodium salt during the charge and discharge process to promote the uniform deposition of sodium ions and copper ions, thereby suppressing problems such as copper ion shuttle diffusion, and ensuring the stable operation of the sodium-copper bimetallic deposition solvent-based reversible battery. In addition, the ether electrolyte can be prepared by uniformly stirring the sodium salt and the organic solvent at room temperature, and the ether electrolyte is used to suppress the dendrite growth of the sodium-copper battery. The method is simple, easy to operate, highly efficient, and low-cost, and can meet the needs of large-scale industrial production and commercial applications.

[0028] In some embodiments, the ester organic solvent includes, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), and fluoroethylene carbonate (FEC).

[0029] In some embodiments, the ether organic solvent includes, but is not limited to, one or more of tetrahydrofuran (THF), ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DIGLYME), triethylene glycol dimethyl ether (TRIGLYME), and tetraethylene glycol dimethyl ether (TETRAGLYME). Ether organic solvents are combined with ester organic solvents to regulate the composition of the SEI (increase the NaF content), enhance interfacial stability, and thus inhibit dendrites and side reactions. The role of ether organic solvents and ester organic solvents in sodium metal batteries is mainly reflected in the improvement of interfacial stability, the optimization of kinetic performance, and the enhancement of wide temperature range adaptability. Ether organic solvents solve the challenge of high rate through weak solvation effect, while ester organic solvents enhance interfacial passivation and safety performance through fluorinated decomposition products.

[0030] In some embodiments, the volume ratio of the ether organic solvent to the ester organic solvent is (5-8):(2-4). The organic solvent and sodium salt mixed in this volume ratio form an ether electrolyte system that can improve interfacial stability, optimize kinetic performance, and enhance wide temperature range adaptability in sodium metal batteries.

[0031] In some embodiments, the volume ratio of the ether organic solvent to the ester organic solvent is 7:3.

[0032] In some embodiments, the sodium salt includes, but is not limited to, one or more of sodium bis(trifluoromethylsulfonyl)imide (NaTFSI), sodium bis(fluorosulfonyl)imide (NaFSI), sodium hexafluorophosphate (NaPF6), sodium perchlorate (NaClO4), sodium bis(oxalatoborate) (NaBOB), sodium tetrafluoroborate (NaBF4), sodium hexafluoroarsenate (NaAsF6), and sodium trifluoromethylsulfonate (NaOTF). Sodium salts are ionized in organic solvents to generate sodium ions, which serve as an ion source during the battery's charge and discharge process. This provides a basic condition for the transport of sodium ions, enabling sodium ions to move back and forth between the positive and negative electrodes, thereby achieving the mutual conversion of electrical energy and chemical energy.

[0033] In some embodiments, the concentration of the sodium salt in the ether electrolyte is 0.1 mol / L-5 mol / L. Controlling the concentration of the sodium salt within the above range can better provide the ion requirements of the battery during the charge and discharge process.

[0034] In some embodiments, the concentration of the sodium salt can be 0.1mol / L, 0.4mol / L, 0.7mol / L, 1mol / L, 1.1mol / L, 1.3mol / L, 1.6mol / L, 2mol / L, 2.4mol / L, 2.6mol / L, 3mol / L, 3.1mol / L, 3.5mol / L, 4mol / L, 4.1mol / L, 4.5mol / L, 5mol / L, but is not limited thereto.

[0035] In some embodiments, the ether organic solvent is tetrahydrofuran, and the ester organic solvent is fluoroethylene carbonate. Fluoroethylene carbonate decomposes to form a SEI film on the surface of the sodium electrode, with a dense inner layer of NaF and an outer porous organic layer. The SEI film inhibits dendrite growth on the sodium surface, significantly reducing the overpotential for sodium deposition. Furthermore, the weak solvation effect of tetrahydrofuran addresses the challenge of high rates.

[0036] Specifically, the copper electrodeposition process is studied in real time by using electrochemical piezoelectric quartz crystal microbalance (EQCM) analysis technology. If the deposited film uniformly distributed on the substrate surface is rigid, the relationship between the mass change Δm (unit g) and the frequency shift value Δf (unit Hz) during its deposition and dissolution process will satisfy the Sauerbrey equation. Combining the Sauerbrey equation (Equation (1)) and Faraday's law (Equation (2)), a quantitative relationship between the mass change and the amount of electricity consumed during the electrode reaction (Q, unit C) can be obtained. Plotting Δm against Q, as shown in the following example: Figure 1 As shown, the calculated theoretical value of M / n is 56.83 g / mol, which shows that Cu is oxidized to monovalent copper ions.

[0037] Δf=-2.264×10-6 fogΔm / A (1)

[0038] Δm / M=Q / (nF) (2)

[0039] In this embodiment, FEC participates in the construction of [Cu 2+ (FEC)2(Solvent) n ] 2+ The solvation sheath of FEC reduces the desolvation energy of copper ions and promotes the uniform deposition / dissolution of copper ions; molecular dynamics simulation shows that the strong polarity of FEC (dipole moment 4.2D) weakens the coordination strength between copper ions and solvents, accelerating interfacial mass transfer; in situ optical microscopy observations show that the porosity of the copper deposit in the FEC-containing electrolyte is less than 5%, while it is as high as 35% when no FEC is added. It can be seen that adding FEC to the electrolyte can improve the coulombic efficiency and cycle life of sodium metal batteries during the charge and discharge process.

[0040] In addition, Figure 2 As shown, the present invention also provides a sodium-copper battery, comprising a sodium negative electrode, a copper positive electrode, a separator disposed between the sodium negative electrode and the copper negative electrode, and an ether electrolyte immersing the sodium negative electrode and the copper positive electrode.

[0041] In this embodiment, an ester organic solvent is added to the ether electrolyte of a sodium-copper battery. Based on the principle of the "solvation-interface" regulation strategy in ion selective transport, the ester organic solvent is decomposed to form a gradient solid electrolyte interface (SEI) film to inhibit the growth of sodium dendrites on the surface, thereby significantly reducing the overpotential of sodium deposition. At the same time, the above-mentioned ether electrolyte is combined with the separator in the sodium-copper battery to effectively inhibit the shuttle of copper ions from the positive electrode to the negative electrode, which can effectively improve the coulombic efficiency and maintain good cycling stability. Furthermore, the ether organic solvent and the ester organic solvent form a solvation property with the sodium salt during the charge and discharge process, promoting the uniform deposition of sodium and copper ions, thereby suppressing the shuttle diffusion of copper ions and other problems, and ensuring the stable operation of the sodium-copper bimetallic deposition solvent-based reversible battery. In addition, the "solvation-interface" regulation strategy can be extended to metal battery systems such as lithium / potassium, and provide a new method for the selective deposition / stripping of such metal ions.

[0042] In some embodiments, as Figure 2 As shown, the separator is composed of a composite membrane of polypropylene and polyimide (PIL / PP) and glass fiber membranes disposed on both sides of the composite membrane. Combining this ether electrolyte with the separator in a sodium-copper battery can effectively inhibit the shuttling of copper ions from the positive electrode to the negative electrode, effectively improving coulombic efficiency and maintaining good cycle stability.

[0043] In some embodiments, the sodium negative electrode is a sodium metal sheet; the copper positive electrode is one of a copper sheet, copper foam, and copper powder; preferably, the copper positive electrode is copper foam, which has a three-dimensional porous structure and serves as a host-free positive electrode. Under the action of the ether electrolyte, the interface stability is enhanced by regulating the composition of SEI (increasing the NaF content), thereby suppressing dendrites and side reactions.

[0044] Specifically, direct charge storage through the reversible copper deposition / dissolution reaction not only eliminates multiple steps, such as cathode slurry preparation, coating, and roller pressing, but also significantly reduces cathode material costs. This method is simple, easy to operate, and low-cost, making it more suitable for industrial production and commercial applications. The resulting sodium-copper bimetallic deposition-dissolution reversible battery exhibits excellent electrochemical performance.

[0045] The present invention will be described in detail with reference to the following examples. It should also be understood that the following examples are only intended to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above disclosure of the present invention fall within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0048] At room temperature, 1.818 g of NaTFSI powder was added to 1.4 mL of THF and 0.6 mL of FEC, mixed evenly and used as an ether electrolyte. A sodium-copper battery was assembled with a sodium metal sheet as the negative electrode, copper foam as the positive electrode, and a glass fiber membrane and PIL / PP as separators.

[0049] The battery is at 1mA cm -2 and 1mAh cm -2 The cycle performance test curve is as follows: Figure 3 As shown in Figure 2, it exhibits excellent high current rate performance and has a high current rate capability at 1 mA cm -2 and 1mAh cm -2 The cycle time is up to 500 hours under normal conditions.

[0050] Comparing the foam copper after 200 cycles with the initial one, the SEM images are as follows Figure 4 As shown (where Figure 4 a and c are copper foams before cycling; b and d are the cells at 1 mA cm -2 and a capacity of 1 mAh cm -2After 200 cycles of operation under the same conditions (a, b are on the same scale, c, d are on the same scale), it was found that the surface structure of the copper foam was slightly damaged, indicating that copper ions can be well deposited on the copper foam. The copper sheet after charge and discharge was analyzed by XRD. Figure 5 As shown in Figure 3, in situ X-ray diffraction (XRD) revealed that the copper crystal exhibited significant (220) crystal plane preferred orientation growth characteristics, and the atomic stacking density of this crystal plane was low (0.74), providing more insertion channels for sodium ions.

[0051] Example 2

[0052] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0053] At room temperature, 1.818 g of NaTFSI powder was added to 1.4 mL of THF and 0.6 mL of FEC, and the mixture was used as an ether electrolyte. A sodium metal sheet was used as the negative electrode, a copper sheet was used as the positive electrode, and a glass fiber membrane and PIL / PP were used as separators to assemble a sodium-copper battery. The battery was tested at 0.5 mA cm -2 and 0.5 mAh cm -2 The cycle time is up to 800 hours under normal conditions.

[0054] Example 3

[0055] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0056] At room temperature, 1.218 g of NaFSI powder was added to 1.4 mL of THF and 0.6 mL of FEC, and the mixture was used as an ether electrolyte. A sodium-copper battery was assembled with a sodium metal sheet as the negative electrode, copper foam as the positive electrode, and a glass fiber membrane and PIL / PP as separators. The battery was tested at 1 mA cm -2 and 0.25 mAh cm -2 The cycle time is up to 400 hours under normal conditions.

[0057] Example 4

[0058] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0059] At room temperature, 1 g of NaPF6 powder was added to 1.4 mL of THF and 0.6 mL of FEC, and the mixture was used as an ether electrolyte. A sodium metal sheet was used as the negative electrode, copper foam was used as the positive electrode, and glass fiber membrane and PIL / PP were used as separators to assemble a sodium-copper battery. The battery was tested at 1 mA cm -2 and 0.5 mAh cm -2 The cycle time is up to 400 hours under normal conditions.

[0060] Example 5

[0061] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0062] At room temperature, 2.122 g of NaTFSI powder was added to 1.4 mL of THF and 0.6 mL of FEC, mixed evenly and used as an ether electrolyte. A sodium-copper battery was assembled with a sodium metal sheet as the negative electrode, copper foam as the positive electrode, and a glass fiber membrane and PIL / PP as separators. The battery was tested at 0.5 mA cm -2 and 0.5 mAh cm -2 The cycle time is up to 700 hours under normal conditions.

[0063] Example 6

[0064] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0065] At room temperature, 1.169 g of NaPF6 powder was added to 1.4 mL of THF and 0.6 mL of FEC, mixed evenly and used as an ether electrolyte. A sodium metal sheet was used as the negative electrode, a copper sheet was used as the positive electrode, and a glass fiber membrane and PIL / PP were used as separators to assemble a sodium-copper battery. The battery was tested at 1 mA cm -2 and 0.25 mAh cm -2 The cycle time is up to 450 hours under normal conditions.

[0066] Example 7

[0067] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0068] At room temperature, 1.421 g of NaFSI powder was added to 1.4 mL of THF and 0.6 mL of FEC, mixed evenly and used as an ether electrolyte. A sodium metal sheet was used as the negative electrode, a copper sheet was used as the positive electrode, and a glass fiber membrane and PIL / PP were used as separators to assemble a sodium-copper battery. The battery was tested at 0.5 mA cm-2 and 1mAh cm -2 The cycle time is up to 500 hours under normal conditions.

[0069] Example 8

[0070] This embodiment provides an ether electrolyte for a sodium-copper bimetallic deposition dissolution type reversible battery, and uses the ether electrolyte to assemble a sodium-copper battery. The preparation method is as follows:

[0071] Copper powder, Ketjen black and PVDF were mixed evenly in a mass ratio of 7:2:1 using NMP as solvent, and then evenly coated on copper foil; the copper foil loaded with copper powder was then placed in a vacuum drying oven at 60°C and dried for 12 hours, and then the copper foil was cut into discs with a diameter of 12 mm as the positive electrode.

[0072] At room temperature, 1.818 g of NaTFSI powder was added to 1.4 mL of THF and 0.6 mL of FEC, mixed evenly and used as an ether electrolyte. A sodium metal sheet was used as the negative electrode, the copper powder electrode sheet was used as the positive electrode, and a glass fiber membrane and PIL / PP were used as separators to assemble a sodium-copper battery. The battery was tested at 0.5 mA cm -2 and 0.5 mAh cm -2 The cycle time is up to 600 hours under normal conditions.

[0073] In summary, the present invention provides an ether electrolyte and a sodium-copper battery. The ether electrolyte comprises a sodium salt and an organic solvent; the organic solvent comprises an ether organic solvent and an ester organic solvent; the ester organic solvent comprises one or more of ethylene carbonate, propylene carbonate, and fluoroethylene carbonate. The present invention adds an ester organic solvent to the ether electrolyte of the sodium-copper battery, utilizing the decomposition of the ester organic solvent to form a gradient solid electrolyte interface (SEI) film to inhibit dendrite growth on the sodium surface, thereby significantly reducing the overpotential for sodium deposition. Furthermore, combining the ether electrolyte with the separator in the sodium-copper battery effectively inhibits the shuttling of copper ions from the positive electrode to the negative electrode, effectively improving coulombic efficiency and maintaining good cycle stability.

[0074] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. An ether electrolyte, characterized in that include: Sodium salt and an organic solvent; the organic solvent consists of an ether organic solvent and an ester organic solvent.

2. The ether electrolyte according to claim 1, characterized in that The ester organic solvent includes one or more of ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.

3. The ether electrolyte according to claim 1, characterized in that The ether organic solvent includes one or more of tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

4. The ether electrolyte according to claim 1, characterized in that The volume ratio of the ether organic solvent to the ester organic solvent is (5-8):(2-4).

5. The ether electrolyte according to claim 4, characterized in that The volume ratio of the ether organic solvent to the ester organic solvent is 7:

3.

6. The ether electrolyte according to claim 1, characterized in that The sodium salt includes one or more of sodium bis(trifluoromethylsulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium hexafluorophosphate, sodium perchlorate, sodium bis(oxalatoborate), sodium tetrafluoroborate, sodium hexafluoroarsenate, and sodium trifluoromethylsulfonate.

7. The ether electrolyte according to claim 1, characterized in that In the ether electrolyte, the concentration of the sodium salt is 0.1 mol / L-5 mol / L.

8. The ether electrolyte according to claim 1, characterized in that The ether organic solvent is tetrahydrofuran; the ester organic solvent is fluoroethylene carbonate.

9. A sodium-copper battery, characterized in that: The invention comprises a sodium negative electrode, a copper positive electrode, a separator arranged between the sodium negative electrode and the copper negative electrode, and the ether electrolyte according to any one of claims 1 to 8 in which the sodium negative electrode and the copper positive electrode are immersed.

10. The sodium-copper battery according to claim 9, characterized in that The diaphragm consists of a composite membrane of polypropylene and polyimide and glass fiber membranes arranged on both sides of the composite membrane.

Images