Sodium metal negative electrode self-supporting material and preparation method and application thereof
By treating carbon cloth with atmospheric pressure plasma, N and O elements are introduced to improve their sodium philtrum, and the problem of low battery performance caused by high activity of sodium metal negative electrode materials is solved, achieving more stable electrochemical performance and higher capacity retention capabilities.
Patent Information
- Application Number
- CN202411493473.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-24
- Publication Date
- 2025-03-11
AI Technical Summary
The existing sodium metal negative electrode materials have low efficiency, limited circulation and safety risks due to their high activity, large volume changes, unstable SEI layer, and uncontrolled dendritic growth.
By treating commercial carbon cloth atmospheric pressure plasma, high electronegative elements such as N and O are introduced to improve the sodium philtrology of carbon-based materials, thereby preparing self-supporting materials for sodium metal negative electrodes.
The carbon cloth material after plasma treatment exhibits a lower nucleation overpotential, which improves the electrochemical performance of the sodium metal negative electrode, enhances the stability and capacity retention ability of the battery, avoids complex chemical processing processes, and is suitable for large-scale production.
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Figure CN119601600A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of sodium metal negative electrode, and in particular to a sodium metal negative electrode self-supporting material and a preparation method and application thereof. Background Art
[0002] Metallic sodium (Na) has been considered as a highly competitive negative electrode for the next generation of rechargeable batteries. However, its high activity, large volume change, unstable SEI layer, uncontrolled dendrite growth and other disadvantages lead to low Coulombic efficiency, limited cyclability and even safety risks of high energy density batteries directly using sodium metal as negative electrode, which greatly inhibits its practical application.
[0003] In order to overcome these problems, various strategies include customizing electrolyte formulations, using solid electrolytes, creating artificial SEI, designing nanostructured Na negative electrodes, etc. Among them, the structural design based on carbon as the host is one of the materials that is expected to solve the problem of sodium metal negative electrodes due to its abundant sources, adjustable structure, good mechanical properties, etc. However, carbon-based materials such as carbon fibers themselves are not affinity to sodium and need to be modified. Doping with highly electronegative elements (N, O, S, P, etc.) is one of the main methods to improve the sodium affinity of carbon substrates, but the current doping methods are mainly in situ polymerization and high-temperature calcination. The treatment process is complicated and lengthy, and involves the use of toxic reagents, which cannot meet the needs of large-scale production of battery production lines. There is an urgent need for a simple and quick way to improve the sodium affinity of carbon substrates. Summary of the invention
[0004] The purpose of the present invention is to provide a sodium metal negative electrode self-supporting material and a preparation method and application thereof in view of the above-mentioned deficiencies in the prior art.
[0005] The invention discloses a method for preparing a sodium metal negative electrode self-supporting material. The method comprises the following steps: ultrasonically cleaning a commercial carbon cloth, drying the carbon cloth and then treating the carbon cloth in a plasma treatment machine under atmospheric pressure to obtain the sodium metal negative electrode self-supporting material.
[0006] Furthermore, the irradiation time of the plasma treatment machine is 30-120s; the irradiation power is 500w.
[0007] Furthermore, the model of the plasma processor is CTP-2000K.
[0008] Furthermore, the commercial carbon cloth was ultrasonically cleaned in ethanol / water, respectively.
[0009] Furthermore, the ethanol is anhydrous ethanol, the water is deionized water, and the cleaning time is 30 minutes.
[0010] A sodium metal negative electrode self-supporting material prepared by the above-mentioned preparation method.
[0011] A sodium metal negative electrode adopts the above-mentioned sodium metal negative electrode self-supporting material as a substrate.
[0012] Further, sodium metal is electrodeposited on the substrate.
[0013] Furthermore, the sodium metal electrodeposition capacity is 3-12 mAh / cm 2 .
[0014] A sodium metal battery comprises the sodium metal negative electrode.
[0015] (1) The present invention proposes for the first time to treat carbon cloth by atmospheric pressure plasma, introduce highly electronegative elements such as N and O into the carbon cloth to improve the sodium affinity of the carbon cloth, and use it as a self-supporting material for the sodium metal negative electrode.
[0016] (2) The plasma-treated carbon cloth exhibits a lower nucleation overpotential for sodium metal. The symmetrical battery assembled with the sodium metal anode prepared by the plasma-treated carbon cloth exhibits better electrochemical performance, a smaller voltage distribution, and more stable operation.
[0017] (3) The full battery assembled with a sodium metal negative electrode prepared from plasma-treated carbon cloth and a sodium vanadium phosphate positive electrode has a higher initial capacity, smaller polarization, and better capacity stability.
[0018] (4) The processing method of the present invention is simple to operate and the process is controllable. It avoids the complicated chemical treatment process and has the prospect of large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 FT-IR characterization diagram of carbon cloth and plasma treated carbon cloth;
[0020] Figure 2 Nucleation overpotential results of constant current charge and discharge test for symmetrical battery on blue power system;
[0021] Figure 3 The voltage-time distribution of a symmetrical battery in a constant current charge and discharge test on a blue power system;
[0022] Figure 4 The test results of the full battery charge and discharge cycle in the voltage range of 2.3-4V and the current density of 10C;
[0023] Figure 5 This is a scanning electron microscope image of the sodium-plasma carbon cloth after 100 charge-discharge cycles;
[0024] Figure 6 This is a scanning electron microscope image of carbon cloth without plasma treatment after 100 charge and discharge cycles. DETAILED DESCRIPTION
[0025] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0026] Example 1
[0027] (1) The commercial carbon cloth was ultrasonically cleaned in ethanol / water respectively.
[0028] (2) Drying the carbon cloth obtained in step (1) in a vacuum oven.
[0029] (3) treating the dried carbon cloth obtained in step (2) in an atmospheric pressure plasma treatment machine.
[0030] In the step (1), the ethanol is anhydrous ethanol, the water is deionized water, and the washing time is 30 minutes.
[0031] The drying temperature in step (2) is 60 degrees Celsius and the drying time is 12 hours.
[0032] In the step (3), the irradiation time of the plasma treatment machine is 60s and the irradiation power is 500w.
[0033] The carbon cloth and the carbon cloth treated with plasma in Example 1 were characterized by FT-IR. Figure 1 shown.
[0034] Compared with the original carbon cloth, the infrared characteristic peaks of C=O bond and C=N bond of the plasma-treated carbon cloth are significantly enhanced, proving that plasma treatment introduces N and O elements into the carbon cloth. N and O elements are more electronegative than C elements and are more affinity to sodium. Compared with the original untreated carbon cloth, the plasma-treated carbon cloth used as the host material of the sodium metal negative electrode exhibits more stable electrochemical performance.
[0035] Comparative Example 1
[0036] Commercial carbon cloth without treatment.
[0037] Example 2
[0038] The nucleation overpotential of the sodium metal anode was studied in a host half-cell.
[0039] Electrodeposition of sodium metal on a self-supporting material comprises the following steps: assembling a half-cell on a plasma-treated carbon cloth and a sodium metal wafer, and performing electrodeposition on a blue electric system.
[0040] The steps for assembling the half-cell are: sodium metal disc as the negative electrode, glass fiber as the separator, carbon cloth obtained by plasma treatment as the positive electrode, and ether sodium salt as the electrolyte. The button cell is assembled in a glove box with an argon atmosphere. The electrodeposition step is carried out on a blue electric system. At the same time, the nucleation overpotential data is obtained.
[0041] The diameter of the sodium metal disc is 10-16 mm.
[0042] The glass fiber diaphragm is whatman GF / A or GF / D.
[0043] The diameter of the carbon cloth obtained by plasma treatment is 10-16 mm.
[0044] The ether sodium salt electrolyte is NaPF 6 Dissolved in diethylene glycol dimethyl ether, the concentration is 1 M. The dosage is 50-200uL.
[0045] The button battery model is celgard CR2032.
[0046] The electrodeposition steps are: 0.5 mA / cm 2 The current density of 3 mAh / cm2 was deposited on the plasma treated carbon cloth. 2 of metallic sodium.
[0047] See also Figure 2 The black line is the nucleation overpotential of the carbon cloth without plasma treatment as the host material of the sodium metal negative electrode, which is calculated to be 25mV. The green line is the nucleation overpotential of the carbon cloth treated with plasma as the host material of the sodium metal negative electrode, which is calculated to be 12mV.
[0048] Depend on Figure 2 It can be seen that the plasma-treated carbon cloth as the host of the sodium metal negative electrode has a lower nucleation overpotential for sodium metal, which is more conducive to the nucleation and growth of sodium metal on the surface of the plasma-treated carbon cloth.
[0049] Example 3
[0050] Symmetrical batteries assembled with sodium metal anode were used to study their voltage distribution.
[0051] The specific operating conditions and results of the experiment are as follows:
[0052] A certain amount of metallic sodium was electrodeposited on plasma-treated carbon cloth, and then a symmetrical battery was assembled to observe the voltage-time distribution of the metallic sodium during repeated deposition and stripping.
[0053] The electrodeposition steps are: sodium metal disc as negative electrode, glass fiber as separator, carbon cloth obtained by plasma treatment as positive electrode, and ether sodium salt as electrolyte. Button cells are assembled in a glove box with argon atmosphere. The electrodeposition steps are carried out on a blue electric system.
[0054] The diameter of the sodium metal disc is 10-16 mm.
[0055] The glass fiber diaphragm is whatman GF / A or GF / D.
[0056] The diameter of the carbon cloth obtained by plasma treatment is 10-16 mm.
[0057] The ether sodium salt electrolyte is NaPF 6 Dissolved in diethylene glycol dimethyl ether, the concentration is 1 M. The dosage is 50-200uL.
[0058] The button battery model is celgard CR2032.
[0059] The electrodeposition steps are as follows: a current density of 0.5 mA / cm2 is used to deposit a capacity of 12 mAh / cm2 on the plasma treated carbon cloth. 2 of metallic sodium.
[0060] The steps of assembling the symmetrical battery are as follows: using the sodium plasma-coated carbon cloth obtained by electrodeposition as the positive and negative electrodes of the symmetrical battery, using glass fiber as the separator, and using ether sodium salt as the electrolyte, and assembling the symmetrical battery in an argon-filled glove box. The symmetrical battery is tested for constant current charge and discharge on the Blue Electric system.
[0061] The glass fiber diaphragm is whatman GF / A or GF / D.
[0062] The ether sodium salt electrolyte is NaPF 6 Dissolved in diethylene glycol dimethyl ether, the concentration is 1 M. The dosage is 50-200uL.
[0063] The button battery model is celgard CR2032.
[0064] The constant current charging and discharging steps are: 1mA / cm 2 The current density is discharged to a capacity of 1 mAh / cm 2 By the end, recharge to a capacity of 1 mAh / cm 2 As of now, the current density is 1mA / cm 2 .
[0065] See also Figure 3 , the black line is the voltage-time distribution of the symmetric battery assembled with carbon cloth that has not been treated with plasma as the host material for the sodium metal anode, and the green line is the voltage-time distribution of the symmetric battery assembled with carbon cloth that has been treated with plasma as the host material for the sodium metal anode.
[0066] Depend on Figure 3 It can be seen that the symmetrical battery obtained by using plasma-treated carbon cloth as the host of the sodium metal negative electrode has a smaller voltage distribution and more stable operation.
[0067] Example 4
[0068] Sodium metal anode full battery test method
[0069] A certain amount of metallic sodium is electrodeposited on the plasma-treated carbon cloth, and the carbon cloth with deposited metallic sodium is used as the negative electrode and sodium vanadium phosphate as the positive electrode to carry out a full battery test.
[0070] The sodium metal electrodeposition capacity is 9 mAh / cm 2
[0071] The preparation method of sodium vanadium phosphate positive electrode is as follows: a uniform slurry is formed in NMP according to the mass ratio of sodium vanadium phosphate: carbon black: PVDF 8:1:1, and then evenly coated on aluminum foil and dried in vacuum at 80 degrees for 12 hours, and then punched into a disc with a diameter of 10 mm on a punching machine for positive electrode, wherein the active material loading of sodium vanadium phosphate is about 0.7 mg / cm 2 The separator used in the full battery is PP and the electrolyte is 1M NaPF 6 in DEGDME.
[0072] The charge and discharge cycle test was carried out in the voltage range of 2.3-4V with a current density of 10C. Figure 4 As shown in the figure, under the charge and discharge of the full battery at 10C, the sodium-plasma carbon cloth negative electrode exhibits a higher initial capacity and smaller polarization than the sodium-carbon cloth negative electrode. After 100 cycles of charge and discharge, the capacity decay of the full battery assembled with the sodium-plasma carbon cloth negative electrode is smaller. This is attributed to the introduction of more sodium-philic N and O elements into the carbon cloth after plasma treatment. During the charge and discharge process, the deposition-stripping process of sodium is more stable, and the full battery exhibits better stability.
[0073] Figure 5 This is a scanning electron microscope image of the sodium-plasma carbon cloth after 100 charge-discharge cycles; Figure 6 This is a scanning electron microscope image of the carbon cloth without plasma treatment after 100 charge and discharge cycles. Figure 5 and Figure 6 It can be seen that after repeated deposition and stripping, the sodium metal on the carbon cloth without plasma treatment appears in the area of aggregation, while on the carbon cloth after plasma treatment, the sodium metal is still evenly distributed along the direction of the fiber after repeated deposition and stripping, and the picture still shows the morphology of the carbon cloth. This proves that after the plasma-treated carbon cloth introduces elements with strong sodium affinity such as N and O, the N and O elements can guide the uniform deposition of sodium during the deposition and stripping process of sodium metal.
[0074] For matters not mentioned above, the prior art applies.
[0075] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a sodium metal negative electrode self-supporting material, characterized in that: The commercial carbon cloth is ultrasonically cleaned, dried, and then treated in a plasma treatment machine under atmospheric pressure to obtain the sodium metal negative electrode self-supporting material.
2. The preparation method according to claim 1, characterized in that: The irradiation time of the plasma treatment machine is 30-120s; the irradiation power is 500w.
3. The preparation method according to claim 1, characterized in that: The model of the plasma treatment machine is CTP-2000K.
4. The preparation method according to claim 1, characterized in that: Commercial carbon cloth was ultrasonically cleaned in ethanol / water respectively.
5. The preparation method according to claim 4, characterized in that: The ethanol is anhydrous ethanol, and the water is deionized water; the cleaning time is 30 minutes.
6. A sodium metal negative electrode self-supporting material prepared by the preparation method according to any one of claims 1 to 5.
7. A sodium metal negative electrode, characterized in that: The sodium metal negative electrode self-supporting material according to claim 6 is used as a substrate.
8. The sodium metal negative electrode according to claim 7, characterized in that: Sodium metal is electrodeposited on a substrate.
9. The sodium metal negative electrode according to claim 7, characterized in that: Sodium metal electrodeposition capacity is 3-12 mAh / cm 2 .
10. A sodium metal battery, characterized in that: Comprising the sodium metal negative electrode as described in claims 7-9.