Tantalum single atom coordinated carbon nitride modified copper current collector and preparation method and sodium battery

Abstract

The present invention relates to the technical field of sodium batteries, and particularly to a tantalum single atom coordinated carbon nitride modified copper current collector, a preparation method thereof, and a sodium battery. The tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) provided by the present invention is prepared by firstly coordinating a tantalum single atom to a graphite-like carbon nitride (g-C3N4) by a two-step annealing method to obtain a tantalum single atom catalyst (Ta-SA / C3N4), and then coating the single atom catalyst on a copper foil. The single atom tantalum prepared by the preparation method has an ultra-high density. The carbon nitride contains 15wt%-20wt% of tantalum metal. The tantalum single atom coordinated carbon nitride can improve sodium affinity, regulate the sodium metal electrodeposition process, greatly reduce the generation of sodium dendrites and "dead sodium", thereby improving the cycle stability and life of the battery. The problem of uncontrollable sodium dendrite growth easily occurring at the sodium metal negative electrode in the prior art, which leads to a decrease in the cycle performance of the sodium battery, is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium batteries, and in particular to a tantalum single atom coordinated carbon nitride modified copper current collector, a preparation method thereof, and a sodium battery. Background Art

[0002] Rechargeable lithium-ion batteries dominate the portable electronics and electric vehicle markets due to their high energy density, light weight, and environmental friendliness. However, the scarcity of lithium resources and rising costs have made the application of lithium batteries in large-scale energy storage challenging. Sodium metal has similar physical and chemical properties to lithium and abundant natural abundance. Researchers have identified sodium-ion batteries as a highly promising alternative to lithium-ion batteries. This is because sodium metal has a high theoretical specific capacity, a low redox potential, and a low cost. However, the practical application of sodium metal anodes is hindered by dendrite growth, resulting in low energy efficiency, poor lifespan, and serious safety issues. As a result, the commercialization of sodium metal anodes has been severely hindered, and mass production and application have not yet been achieved.

[0003] Therefore, to address these issues and achieve the commercialization of high-energy-density and safe sodium metal batteries, efforts must be made to mitigate or even eradicate the problem of sodium dendrite growth. Modifying the sodium metal anode current collector can reduce the local current density for sodium nucleation, induce uniform sodium deposition, and inhibit volume expansion. In particular, pre-storing sodium metal on the current collector by electrodeposition can effectively regulate the stoichiometry of the sodium metal anode, avoid excessive sodium metal use, improve utilization, and effectively prevent potential safety risks in practical applications.

[0004] The current density and chemical properties on the current collector surface are important factors in regulating the sodium nucleation behavior. Using single-atom catalysts to generate active sites with high sodium affinity on the current collector surface can effectively disperse the sodium ion flux and local charge density to achieve a uniform electric field distribution, thereby regulating the sodium nucleation process and guiding the uniform deposition of sodium metal. It is an effective way to solve the problem of sodium dendrite growth.

[0005] However, in the prior art, single-atom catalysts have not yet been used in sodium battery modified copper current collectors. Patent document CN118380540B discloses a sodium ion battery negative electrode sheet, its preparation method and application, and a sodium ion battery, relating to the field of battery technology. The sodium ion battery negative electrode sheet provided by the invention includes a current collector and a three-dimensional carbon metal layer and a negative electrode material layer sequentially coated on the current collector; the three-dimensional carbon metal layer includes a three-dimensional carbon material and metal particles supported on the three-dimensional carbon material; the three-dimensional carbon material is mainly composed of point-type carbon material, linear carbon material, and surface-type carbon material; the metal particles include copper particles or copper alloy particles; and the three-dimensional carbon metal layer is negatively charged.

[0006] However, these existing battery systems will also generate a large amount of sodium dendrites and "dead sodium", thereby reducing the cycle stability and life of the battery; therefore, the existing technology still has the problem that the sodium metal negative electrode is prone to uncontrollable sodium dendrite growth, resulting in a decrease in the cycle performance of the sodium battery.

[0007] Therefore, according to the above-mentioned related technologies, it is urgent to develop a tantalum single atom coordinated carbon nitride modified copper current collector and its preparation method and sodium battery. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to propose a tantalum single atom coordinated carbon nitride modified copper current collector and its preparation method and sodium battery, so as to solve the technical problem in the prior art that uncontrollable sodium dendrite growth easily occurs in the sodium metal negative electrode, resulting in a decrease in the cycle performance of the sodium metal battery.

[0009] Based on the above objectives, the present invention provides a tantalum single atom coordinated carbon nitride modified copper current collector, a preparation method and a sodium battery.

[0010] A method for preparing a copper current collector modified by tantalum single atom coordinated carbon nitride, the preparation method is as follows:

[0011] Step S1: thermally polymerizing melamine to obtain graphite-like carbon nitride;

[0012] Step S2: mixing tantalum chloride and graphite-like carbon nitride and then performing a two-step annealing process to obtain a tantalum single-atom catalyst;

[0013] Step S3: coating a tantalum single atom catalyst on a copper foil to obtain a tantalum single atom coordinated carbon nitride modified copper current collector;

[0014] The content of tantalum metal doped in the carbon nitride in step S3 is 15 wt%-20 wt%.

[0015] Preferably, the process of thermal polymerization of melamine in step S1 is as follows:

[0016] Melamine is heated to 400-800° C. at a rate of 3-6° C. / min under an argon atmosphere and kept at this temperature for 2-6 hours. The melamine is then cooled to room temperature and ground to obtain graphite-like carbon nitride.

[0017] Preferably, the process of mixing tantalum chloride and graphite-like carbon nitride and then performing a two-step annealing process in step S2 is as follows:

[0018] Step A1: Tantalum chloride and graphite-like carbon nitride are uniformly mixed, and then heated to 300-500°C at 3-6°C / min under a nitrogen atmosphere and kept warm for 2-6 hours. After cooling to room temperature, the mixture is washed with anhydrous ethanol 3-5 times, and finally dried at 80-82°C to obtain a mixed powder;

[0019] Step A2: heating the mixed powder to 400-450° C. at 1-2° C. / min under a nitrogen atmosphere and keeping the temperature for 5-8 hours, and then cooling to room temperature to obtain a tantalum single-atom catalyst.

[0020] Preferably, the mass ratio of tantalum chloride to graphite-like carbon nitride in step A1 is 5-7.5:3-4.5.

[0021] Preferably, the method for coating the tantalum single atom catalyst on the copper foil in step S3 is as follows:

[0022] Tantalum single atom catalyst and polyvinylidene fluoride are added to N-methyl-2-pyrrolidone, mixed evenly and then coated on copper foil, and then dried at 75-80°C to obtain a tantalum single atom coordinated carbon nitride modified copper current collector.

[0023] Preferably, the mass ratio of the tantalum single-atom catalyst to polyvinylidene fluoride is 8-10:2-2.5.

[0024] A sodium battery is prepared by using a tantalum single atom coordinated carbon nitride modified copper current collector.

[0025] Preferably, the sodium battery is any one of a half cell and a symmetrical cell;

[0026] The positive electrode of the half-cell is a copper current collector modified by tantalum single-atom coordinated carbon nitride;

[0027] The negative electrode of the half-cell is sodium metal;

[0028] The separator of the half-cell is any one of Celgard°3501 separator and Whatman glass fiber;

[0029] The positive electrode and negative electrode of the symmetrical battery are both tantalum single-atom coordinated carbon nitride modified copper current collectors;

[0030] The separator of the symmetrical battery is any one of Celgard°3501 separator and Whatman glass fiber.

[0031] Preferably, the preparation method of the sodium battery electrolyte is as follows:

[0032] Sodium hexafluorophosphate is dissolved in ethylene glycol dimethyl ether to obtain an electrolyte solution.

[0033] Preferably, the concentration of sodium hexafluorophosphate in the electrolyte is 0.5-3 mol / L.

[0034] Beneficial effects of the present invention:

[0035] The present invention provides a tantalum single atom coordinated carbon nitride modified copper current collector, a preparation method, and a sodium battery. The tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) provided by the present invention is prepared by firstly coordinating a tantalum single atom in a graphite-like carbon nitride (g-C3N4) by a two-step annealing method to obtain a tantalum single atom catalyst (Ta-SA / C3N4), and then coating the single atom catalyst on a copper foil. The single atom tantalum prepared by the preparation method has an ultra-high density. The tantalum metal content doped in the carbon nitride is 15wt%-20wt%. The tantalum single atom coordinated carbon nitride can improve sodium affinity, regulate the sodium metal electrodeposition process, greatly reduce the generation of sodium dendrites and "dead sodium", thereby improving the cycle stability and life of the battery. This solves the problem in the prior art that uncontrollable sodium dendrite growth is prone to occur at the sodium metal negative electrode, resulting in a decrease in the cycle performance of the sodium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a comparison chart of X-ray diffraction of the graphite-like carbon nitride (g-C3N4) and the tantalum single atom catalyst (Ta-SA / C3N4) prepared in Example 1 of the present invention;

[0038] Figure 2 The scanning electron microscope image and element content analysis diagram of the tantalum single-atom catalyst (Ta-SA / C3N4) prepared in Example 1 of the present invention;

[0039] Figure 3 This is a graph showing the cycling performance test results of a symmetrical battery after the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) and copper foil prepared in Example 1 of the present invention were assembled;

[0040] Figure 4 This is a graph showing the coulombic efficiency test results of the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) prepared in Example 1 of the present invention and the copper foil after being assembled into a half-cell;

[0041] Figure 5 This is a graph showing the cycling performance test results of a symmetrical battery after the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) and copper foil prepared in Comparative Example 1 of the present invention were assembled;

[0042] Figure 6This is a graph showing the cycling performance test results of a symmetrical battery after the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) and copper foil prepared in Comparative Example 2 of the present invention were assembled;

[0043] Figure 7 This is a graph showing the cycle performance test results of the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) and copper foil prepared in Comparative Example 3 of the present invention after being assembled into symmetrical batteries. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0045] Example 1: A method for preparing a tantalum single atom coordinated carbon nitride modified copper current collector and a sodium battery is as follows:

[0046] S1. Melamine was heated to 500°C at 3°C / min under an argon atmosphere and held for 3 h. After cooling to room temperature, it was ground to obtain graphite-like carbon nitride.

[0047] S2. 0.5 g of tantalum chloride and 0.3 g of graphite-like carbon nitride were mixed, and then heated to 300 ° C at 5 ° C / min under a nitrogen atmosphere and kept warm for 5 h. After cooling to room temperature, the mixture was washed three times with anhydrous ethanol and finally dried at 80 ° C to obtain a mixed powder;

[0048] S3. The mixed powder was heated to 400°C at 2°C / min under a nitrogen atmosphere and kept at this temperature for 5 h, and then cooled to room temperature to obtain a tantalum single atom catalyst;

[0049] S4. 80 mg of tantalum single atom catalyst and 20 mg of polyvinylidene fluoride were added to N-methyl-2-pyrrolidone, mixed evenly, and coated on a copper foil, and then dried at 80 ° C to obtain a tantalum single atom coordinated carbon nitride modified copper current collector;

[0050] S5. Dissolve 5 mmol of sodium hexafluorophosphate in 10 mL of ethylene glycol dimethyl ether to obtain an electrolyte;

[0051] S6. A half-cell was prepared using a tantalum single-atom coordinated carbon nitride-modified copper current collector as the positive electrode, sodium metal as the negative electrode, and a Whatman glass fiber separator.

[0052] S7. A symmetrical battery was obtained by using a copper current collector modified by tantalum single-atom coordinated carbon nitride as the positive electrode, a copper current collector modified by tantalum single-atom coordinated carbon nitride as the negative electrode, Whatman glass fiber as the separator, and assembling the electrolyte.

[0053] Example 2: A method for preparing a tantalum single atom coordinated carbon nitride modified copper current collector and a sodium battery is as follows:

[0054] S1. Melamine was heated to 500°C at 4°C / min under an argon atmosphere and held for 3 h. After cooling to room temperature, it was ground to obtain graphite-like carbon nitride.

[0055] S2. 0.6 g of tantalum chloride and 0.35 g of graphite-like carbon nitride were mixed, and then heated to 350 ° C at 4 ° C / min under a nitrogen atmosphere and kept warm for 3 h. After cooling to room temperature, the mixture was washed four times with anhydrous ethanol and finally dried at 81 ° C to obtain a mixed powder;

[0056] S3. The mixed powder was heated to 400°C at 1°C / min under a nitrogen atmosphere and kept at this temperature for 6 h, and then cooled to room temperature to obtain a tantalum single-atom catalyst;

[0057] S4. 90 mg of tantalum single atom catalyst and 23 mg of polyvinylidene fluoride were added to N-methyl-2-pyrrolidone, mixed evenly, and coated on a copper foil, and then dried at 77 ° C to obtain a tantalum single atom coordinated carbon nitride modified copper current collector;

[0058] S5. Dissolve 10 mmol of sodium hexafluorophosphate in 10 mL of ethylene glycol dimethyl ether to obtain an electrolyte;

[0059] S6. A half-cell was prepared using a tantalum single-atom coordinated carbon nitride-modified copper current collector as the positive electrode, sodium metal as the negative electrode, and a Celgard°3501 separator as the separator. The electrolyte was then assembled.

[0060] S7. A symmetrical battery was obtained by using a copper current collector modified by tantalum single atom coordinated carbon nitride as the positive electrode, a copper current collector modified by tantalum single atom coordinated carbon nitride as the negative electrode, a Celgard°3501 separator, and an electrolyte.

[0061] Example 3: A method for preparing a tantalum single atom coordinated carbon nitride modified copper current collector and a sodium battery is as follows:

[0062] S1. Melamine was heated to 600°C at 5°C / min under an argon atmosphere and held for 5 h, then cooled to room temperature and ground to obtain graphite-like carbon nitride;

[0063] S2. 0.65 g of tantalum chloride and 0.4 g of graphite-like carbon nitride were mixed, and then heated to 450 ° C at 5 ° C / min under a nitrogen atmosphere and kept for 5 h. After cooling to room temperature, it was washed four times with anhydrous ethanol and finally dried at 81 ° C to obtain a mixed powder;

[0064] S3. The mixed powder was heated to 450°C at 1.5°C / min under a nitrogen atmosphere and kept at this temperature for 7 h, and then cooled to room temperature to obtain a tantalum single-atom catalyst;

[0065] S4. 95 mg of tantalum single-atom catalyst and 24 mg of polyvinylidene fluoride were added to N-methyl-2-pyrrolidone, mixed evenly, and coated on a copper foil, and then dried at 78 ° C to obtain a tantalum single-atom coordinated carbon nitride modified copper current collector;

[0066] S5. Dissolve 20 mmol of sodium hexafluorophosphate in 10 mL of ethylene glycol dimethyl ether to obtain an electrolyte;

[0067] S6. A half-cell was prepared using a tantalum single-atom coordinated carbon nitride-modified copper current collector as the positive electrode, sodium metal as the negative electrode, and a Celgard°3501 separator as the separator. The electrolyte was then assembled.

[0068] S7. A symmetrical battery was obtained by using a copper current collector modified by tantalum single atom coordinated carbon nitride as the positive electrode, a copper current collector modified by tantalum single atom coordinated carbon nitride as the negative electrode, a Celgard°3501 membrane as the separator, and assembling the electrolyte.

[0069] Example 4: A method for preparing a tantalum single atom coordinated carbon nitride modified copper current collector and a sodium battery is as follows:

[0070] S1. Melamine was heated to 800°C at 6°C / min under an argon atmosphere and held for 6 h. After cooling to room temperature, it was ground to obtain graphite-like carbon nitride.

[0071] S2. 0.75 g of tantalum chloride and 0.45 g of graphite-like carbon nitride were mixed, and then heated to 500 ° C at 6 ° C / min under a nitrogen atmosphere and kept warm for 6 h. After cooling to room temperature, the mixture was washed five times with anhydrous ethanol and finally dried at 82 ° C to obtain a mixed powder;

[0072] S3. The mixed powder was heated to 450°C at 2°C / min under a nitrogen atmosphere and kept at this temperature for 8 h, and then cooled to room temperature to obtain a tantalum single-atom catalyst;

[0073] S4. 0.1 g of tantalum single atom catalyst and 0.25 g of polyvinylidene fluoride were added to N-methyl-2-pyrrolidone, mixed evenly, and coated on a copper foil, and then dried at 80 ° C to obtain a tantalum single atom coordinated carbon nitride modified copper current collector;

[0074] S5. 30 mmol of sodium hexafluorophosphate was dissolved in 10 mL of ethylene glycol dimethyl ether to obtain an electrolyte;

[0075] S6. A half-cell was prepared using a tantalum single-atom coordinated carbon nitride-modified copper current collector as the positive electrode, sodium metal as the negative electrode, and a Whatman glass fiber separator.

[0076] S7. A symmetrical battery was obtained by using a copper current collector modified by tantalum single-atom coordinated carbon nitride as the positive electrode, a copper current collector modified by tantalum single-atom coordinated carbon nitride as the negative electrode, Whatman glass fiber as the separator, and assembling the electrolyte.

[0077] Comparative Example 1:

[0078] Compared with Example 1, this comparative example only replaces the step of "raising the temperature of the mixed powder to 400° C. at 2° C. / min under a nitrogen atmosphere and keeping the temperature for 5 h" with "raising the temperature of the mixed powder to 500° C. at 3° C. / min under a nitrogen atmosphere and keeping the temperature for 5 h" during the preparation process of the tantalum single-atom catalyst. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a tantalum single-atom coordinated carbon nitride modified copper current collector is obtained;

[0079] Comparative Example 2:

[0080] Compared with Example 1, this comparative example only replaced the "0.5 g tantalum chloride and 0.3 g graphite-like carbon nitride" added during the preparation of the mixed powder with "0.5 g tantalum chloride and 0.4 g graphite-like carbon nitride". The remaining steps and parameters were the same and will not be repeated in this comparative example. Finally, a copper current collector modified with tantalum single atom coordinated carbon nitride was obtained.

[0081] Comparative Example 3:

[0082] Compared with Example 1, this comparative example only replaces the "0.5g tantalum chloride and 0.3g graphite-like carbon nitride" added during the mixed powder preparation process with "0.5g tantalum chloride and 0.2g graphite-like carbon nitride". The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a tantalum single-atom coordinated carbon nitride modified copper current collector is obtained.

[0083] Performance testing and data analysis:

[0084] The structure and performance tests of the tantalum single atom coordinated carbon nitride modified copper current collectors prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were carried out. The structure test included X-ray diffraction test (XRD), scanning electron microscopy analysis (SEM) and energy dispersive spectrum analysis (EDS), and the performance test included cycle performance test. The test results are shown in FIG. Figure 1-Figure 7 As shown;

[0085] in, Figure 1 This is a comparison of the XRD patterns of a copper current collector modified with tantalum single-atom coordinated carbon nitride and its precursor carbon nitride material (g-C3N4). It can be seen that both exhibit only carbon nitride diffraction peaks, attributed to the (100) and (002) crystal planes. There are no diffraction peaks for Ta, indicating that Ta exists in the form of single atoms.

[0086] Figure 2The SEM and EDS images of the tantalum single-atom catalyst (Ta-SA / C3N4) show that the amorphous carbon nitride doped with tantalum atoms maintains its original morphology under the scanning electron microscope. Further, the EDS element content analysis shows that the tantalum metal content doped in the carbon nitride is about 16wt%, which is far higher than the level reported in conventional literature (<10wt%). This confirms that the two-step annealing method of the present invention can prepare an ultra-high-density tantalum single-atom coordinated carbon nitride modified copper current collector.

[0087] In the performance test, the deposition surface capacity was 3 mAh cm -2 Symmetrical cells were assembled using conventional commercial copper foil and the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) prepared in Example 1 and Comparative Examples 1 to 3. The results are shown in FIG. Figure 3 As shown, the overpotential of the symmetrical battery assembled with a conventional copper current collector is about 15 mV, and the cycle life is about 110 h; after the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) prepared in Example 1 of the present application is assembled into a symmetrical battery, its overpotential is reduced to about 7 mV, and the cycle life is extended to more than 700 h; therefore, compared with the symmetrical battery assembled with a conventional copper current collector and the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) prepared in Comparative Examples 1 to Comparative Examples 3, the cycle life of the symmetrical battery assembled with the symmetrical battery in Example 1 of the present invention is greatly improved.

[0088] Coulomb efficiency comparison Figure 4 As shown, the average coulombic efficiency (CE) value of the tantalum single atom coordinated carbon nitride modified copper current collector (Ta-SA / C3N4@Cu) half-cell prepared in Example 1 is as high as 99.6%, and it can be stably cycled for more than 300 cycles. In contrast, the CE of the commercial copper foil half-cell is extremely unstable, with a cycle life of only dozens of cycles. This shows that the single-atom catalyst provided in this application can generate active sites with high sodium affinity on the surface of the current collector, thereby effectively dispersing the sodium ion flux and adjusting the local charge density to achieve a uniform electric field distribution, thereby regulating the sodium nucleation process and guiding the uniform deposition of sodium metal, overcoming the problems of poor cycle performance and short cycle life caused by excessive growth of sodium dendrites in conventional sodium metal batteries.

[0089] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0090] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a copper current collector modified by tantalum single atom coordinated carbon nitride, characterized in that: The preparation method is as follows: Step S1: thermally polymerizing melamine to obtain graphite-like carbon nitride; Step S2: mixing tantalum chloride and graphite-like carbon nitride and then performing a two-step annealing process to obtain a tantalum single-atom catalyst; Step S3: coating a tantalum single atom catalyst on a copper foil to obtain a tantalum single atom coordinated carbon nitride modified copper current collector; The content of tantalum metal doped in the carbon nitride in step S3 is 15wt%-20wt%; The process of thermal polymerization of melamine in step S1 is as follows: Melamine is heated to 400-800°C at 3-6°C / min under an argon atmosphere and kept at this temperature for 2-6 hours, and then ground after cooling to room temperature to obtain graphite-like carbon nitride; The process of mixing tantalum chloride and graphite-like carbon nitride and then performing a two-step annealing process in step S2 is as follows: Step A1: Tantalum chloride and graphite-like carbon nitride are uniformly mixed, and then heated to 300-500°C at 3-6°C / min under a nitrogen atmosphere and kept warm for 2-6 hours. After cooling to room temperature, the mixture is washed with anhydrous ethanol 3-5 times, and finally dried at 80-82°C to obtain a mixed powder; Step A2: heating the mixed powder to 400-450° C. at 1-2° C. / min under a nitrogen atmosphere and keeping the temperature for 5-8 hours, and then cooling to room temperature to obtain a tantalum single-atom catalyst.

2. The method for preparing a copper current collector modified by tantalum single atom coordinated carbon nitride according to claim 1, characterized in that: The mass ratio of tantalum chloride to graphite-like carbon nitride in step A1 is 5-7.5:3-4.

5.

3. The method for preparing a copper current collector modified by tantalum single atom coordinated carbon nitride according to claim 1, characterized in that: The method for coating the tantalum single atom catalyst on the copper foil in step S3 is as follows: Tantalum single atom catalyst and polyvinylidene fluoride are added to N-methyl-2-pyrrolidone, mixed evenly and then coated on copper foil, and then dried at 75-80°C to obtain a tantalum single atom coordinated carbon nitride modified copper current collector.

4. The method for preparing a copper current collector modified by tantalum single atom coordinated carbon nitride according to claim 3, characterized in that: The mass ratio of the tantalum single atom catalyst to polyvinylidene fluoride is 8-10:2-2.

5.

5. A sodium battery, characterized in that: The sodium battery includes a tantalum single-atom coordinated carbon nitride modified copper current collector prepared by the preparation method of a tantalum single-atom coordinated carbon nitride modified copper current collector according to any one of claims 1 to 4.

6. The sodium battery according to claim 5, characterized in that The sodium battery is any one of a half cell and a symmetrical cell; The positive electrode of the half-cell is a copper current collector modified by tantalum single-atom coordinated carbon nitride; The negative electrode of the half-cell is sodium metal; The separator of the half-cell is any one of Celgard°3501 separator and Whatman glass fiber; The positive electrode and negative electrode of the symmetrical battery are both tantalum single-atom coordinated carbon nitride modified copper current collectors; The separator of the symmetrical battery is any one of Celgard°3501 separator and Whatman glass fiber.

7. The sodium battery according to claim 5, characterized in that The preparation method of the electrolyte of the sodium battery is as follows: Sodium hexafluorophosphate is dissolved in ethylene glycol dimethyl ether to obtain an electrolyte solution.

8. The sodium battery according to claim 7, characterized in that The concentration of sodium hexafluorophosphate in the electrolyte is 0.5-3 mol / L.

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