Preparation method of fluorinated negative electrode current collector for negative-electrode-free alkali metal battery and negative-electrode-free alkali metal battery
By fluorinating the negative electrode current collector with quaternary ammonium salt, fluorination product sites are generated on the surface of the current collector, solving the problem of localized accumulation of alkali metal ions in negative electrode-free alkali metal batteries, improving the battery's cycle life and safety, and simplifying the manufacturing process.
Patent Information
- Application Number
- CN202510747044.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-05
- Publication Date
- 2025-09-05
AI Technical Summary
In negative electrode-free alkali metal batteries, alkali metal ions tend to accumulate locally when reduced on the surface of the negative electrode current collector, leading to uncontrollable side reactions and dendrite growth, reducing the battery cycle life and safety. The modification of existing conductive carbon materials increases costs and reduces energy density.
The negative electrode current collector is treated with a quaternary ammonium salt fluorination reagent to generate fluorinated product sites on the current collector surface, which form weak bonds with alkali metal ions through Lewis acid-base interaction, promote uniform deposition, and reduce migration barriers.
The cycle stability and safety of negative electrode-free alkali metal batteries are improved, while maintaining or increasing the energy density and simplifying the battery manufacturing process.
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Figure CN120600832A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of secondary negative electrode-free alkali metal batteries, and particularly relates to a method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery and the negative electrode-free alkali metal battery. Background Art
[0002] Secondary alkali metal batteries have been widely developed and applied in fields such as power vehicles, energy storage power stations, small electronic devices, and aerospace due to their advantages such as long cycle life and high energy density. However, metal negative electrodes are often chemically highly active, which makes their storage and battery preparation process difficult. In addition, the use of alkali metal negative electrodes also increases the difficulty of post-battery recycling. Therefore, the negative electrode-free alkali metal battery formed by not using alkali metal negative electrodes greatly simplifies the battery preparation process, and the battery's mass energy density and volume energy density are further improved, making it an important candidate for the next generation of energy storage and power supply.
[0003] Compared to alkali metal batteries, anode-free alkali metal batteries are characterized by the deposition / stripping process of alkali metal ions on the surface of the anode current collector. However, due to the lack of metal nucleation sites on the anode current collector surface, the reduction of alkali metal ions to alkali metals on the anode current collector surface often leads to localized accumulation of alkali metals, causing uncontrollable side reactions with the electrolyte and dendrite growth, significantly reducing the cycle life and safety of anode-free alkali metal batteries. Currently, most research focuses on coating and modifying the anode current collector surface with a conductive carbon material. However, the use and modification of conductive carbon materials not only reduces the energy density of anode-free alkali metal batteries to a certain extent, but also increases the number of battery manufacturing steps and costs, reducing the energy density and cost advantages of anode-free alkali metal batteries. Therefore, directly chemically treating the anode current collector to create adsorption sites on the current collector surface that are conducive to alkali metal ion deposition is crucial for improving the cycle life and safety of anode-free alkali metal batteries. Summary of the Invention
[0004] In order to solve the problems existing in the prior art, the first object of the present invention is to provide a method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery.
[0005] The second object of the present invention is to provide a negative electrode-free alkali metal battery with long cycle life and high safety.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] The preparation method of the fluorinated negative electrode current collector for negative electrode-free alkali metal batteries comprises the following steps: soaking the negative electrode current collector in a quaternary ammonium salt fluorination reagent, washing the negative electrode current collector after soaking, and vacuum drying to obtain the fluorinated negative electrode current collector.
[0008] Preferably, the quaternary ammonium salt fluorination agent includes any one or more combinations of tetramethylammonium fluoride solution, tetraethylammonium fluoride solution and tetrabutylammonium fluoride solution.
[0009] Preferably, the negative electrode current collector is any one of an aluminum current collector, a copper current collector, a zinc current collector, a lithium-tin alloy, a silver-magnesium alloy and a lithium-indium alloy current collector.
[0010] Preferably, the solvent of the quaternary ammonium salt fluorination agent is tetrahydrofuran.
[0011] Preferably, the concentration of the quaternary ammonium salt fluorination agent is 0.05-2 mol / L.
[0012] Preferably, the negative electrode current collector is immersed in the quaternary ammonium salt fluorination agent for 1-72 hours.
[0013] Preferably, anhydrous ethanol is used to clean the negative electrode current collector.
[0014] A negative electrode-free alkali metal battery comprises a positive electrode, an electrolyte and a negative electrode current collector, wherein the negative electrode current collector is the fluorinated negative electrode current collector.
[0015] Preferably, the negative electrode-free alkali metal battery includes any one of a negative electrode-free sodium metal battery, a negative electrode-free lithium metal battery and a negative electrode-free potassium metal battery.
[0016] Preferably, the electrolyte is an ether-based electrolyte.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] The fluoride ions in the quaternary ammonium salt fluorination reagent have strong Lewis basicity and can preferentially react in situ with the metal current collector. The metal atoms on the surface of the current collector are oxidized to metal cations through Lewis acid-base action. At the same time, the fluoride ions themselves are reduced as electron acceptors, generating abundant fluorination product sites on the surface of the metal current collector. The lone electron pairs of the fluoride ions in the fluorination products can form weakly bound ion pairs with the free alkali metal cations in the electrolyte through coordination, reducing the migration barrier of the alkali metal cations at the interface, guiding them to be uniformly adsorbed on the surface of the current collector, and promoting the uniform reduction of alkali metal cations to alkali metals on the entire surface of the negative electrode current collector, greatly weakening the growth of dendrites, and improving the cycle stability and safety of negative electrode-free alkali metal batteries. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 Figures (a) and (b) are the charge and discharge curves of the asymmetric battery prepared in Example 1 and Comparative Example 1, respectively;
[0020] Figure 2Figures (a) and (b) are the cycle coulombic efficiencies of the asymmetric batteries of Example 2 and Comparative Example 2, respectively;
[0021] Figure 3 Figures (a) and (b) are the charge and discharge curves of the full battery of Example 3 and Comparative Example 3 at a current density of 0.5C, respectively;
[0022] Figure 4 This is the long cycle curve of the full battery of Example 4 at a current density of 0.5C;
[0023] Figure 5 This is the long cycle curve of the full battery of Comparative Example 4 at a current density of 0.5C. DETAILED DESCRIPTION
[0024] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0025] Example 1
[0026] A method for preparing a fluorinated negative electrode current collector for a negative electrode-free sodium metal battery comprises cutting an aluminum negative electrode current collector into discs with a diameter of 14 mm, soaking the discs in a 1 mol / L tetrabutylammonium fluoride solution (solvent: tetrahydrofuran) for 48 hours, removing the current collector discs after soaking, washing them multiple times in anhydrous ethanol, and vacuum drying to obtain an aluminum fluoride negative electrode current collector (F-Al).
[0027] The specific electrochemical test method is as follows:
[0028] The aluminum fluoride negative electrode current collector in Example 1 was used as the research electrode, the sodium metal sheet was used as the counter electrode, and the glass fiber separator and 1 mol / L -Diethylene glycol dimethyl ether electrolyte was assembled into a Na||F-Al 2025 button half-cell at 0.5 mA / cm 2 The current density is used for charge and discharge test, and the results are as follows Figure 1 As shown in (a), the polarization voltage is 36 mV.
[0029] Example 2
[0030] A method for preparing a fluorinated negative electrode current collector for a negative electrode-free lithium metal battery comprises cutting a copper negative electrode current collector into discs with a diameter of 14 mm, soaking the discs in a 2.0 mol / L tetraethylammonium fluoride solution (solvent: tetrahydrofuran) for 48 hours, removing the current collector discs after soaking, washing them multiple times in anhydrous ethanol, and vacuum drying to obtain a fluorinated copper negative electrode current collector (F-Cu).
[0031] The specific electrochemical test method is as follows:
[0032] The copper fluoride negative electrode current collector in Example 2 was used as the research electrode, the lithium metal sheet was used as the counter electrode, and the polypropylene separator and 1 mol / L -Ethylene glycol dimethyl ether electrolyte was assembled into Li||F-Cu 2025 button half-cell at 0.5mA / cm 2 The current density is used for long cycle charge and discharge test, and the results are as follows Figure 2 As shown in (a), the charge and discharge coulombic efficiency is maintained at around 99.8%.
[0033] Example 3
[0034] A method for preparing a fluorinated negative electrode current collector for a negative electrode-free potassium metal battery comprises cutting an aluminum negative electrode current collector into discs with a diameter of 14 mm, soaking the discs in a 2 mol / L tetramethylammonium fluoride solution (solvent: tetrahydrofuran) for 12 hours, removing the current collector discs after soaking, washing them multiple times in anhydrous ethanol, and vacuum drying to obtain an aluminum fluoride negative electrode current collector (F-Al).
[0035] A negative electrode-free potassium metal battery, using the aluminum fluoride negative electrode current collector in Example 3 as the negative electrode current collector of the full battery, Prussian blue (PB) as the positive electrode, and a glass fiber separator and 1 mol / L -Diethylene glycol dimethyl ether electrolyte is assembled into F-Al||PB 2025 type button full battery.
[0036] The specific electrochemical test method is as follows:
[0037] The activation was carried out at a current density of 0.1C and the charge and discharge test was carried out at a current density of 0.5C. The results are as follows Figure 3 As shown in (a), the reversible specific capacity is 138.3 mAh / g.
[0038] Example 4
[0039] A method for preparing a fluorinated negative electrode current collector for a negative electrode-free sodium metal battery comprises cutting a zinc negative electrode current collector into electrode sheets with a diameter of 14 mm, soaking the sheet in a 0.5 mol / L tetrabutylammonium fluoride solution (solvent: tetrahydrofuran) for 12 hours, removing the current collector disc after soaking, washing it multiple times in anhydrous ethanol, and vacuum drying it to obtain a zinc fluoride negative electrode current collector (F-Zn).
[0040] A negative electrode-free sodium metal battery, using the zinc fluoride negative electrode current collector in Example 4 as the negative electrode current collector of the full battery, iron-based Prussian blue (Fe-PB) as the positive electrode, and a glass fiber separator and 1 mol / L -Diethylene glycol dimethyl ether electrolyte was assembled into F-Zn||Fe-PB 2025 button cells.
[0041] The specific preparation method and low-temperature electrochemical performance test are as follows:
[0042] The specific electrochemical test method is as follows:
[0043] The activation was carried out at a current density of 0.1C and the charge and discharge cycle was carried out at a current density of 0.5C. The results are as follows Figure 4 As shown, the initial discharge specific capacity is 153 mAh / g, and after 120 cycles there is still a reversible specific capacity of more than 140 mAh / g.
[0044] Comparative Example 1
[0045] The difference between this comparative example and Example 1 is that a non-fluorinated aluminum negative electrode current collector is used. The other steps and electrochemical test methods are the same as those in Example 1. The experimental results are shown in FIG. Figure 1 As shown in (b), the polarization voltage is 67 mV.
[0046] Comparative Example 2
[0047] The difference between this comparative example and Example 2 is that a non-fluorinated copper negative electrode current collector is used. The other steps and electrochemical test methods are the same as those in Example 2. The experimental results are shown in Figure 2. Figure 2 As shown in (b), the cyclic Coulombic efficiency is extremely unstable.
[0048] Comparative Example 3
[0049] The difference between this comparative example and Example 3 is that a non-fluorinated aluminum negative electrode current collector is used. The other steps and electrochemical test methods are the same as those in Example 3. The experimental results are shown in Figure 3. Figure 3 As shown in (b), the reversible specific capacity is 127.4 mAh / g.
[0050] Comparative Example 4
[0051] The difference between this comparative example and Example 4 is that a non-fluorinated zinc negative electrode current collector is used. The other steps and electrochemical test methods are the same as those in Example 4. The experimental results are shown in Figure 4. Figure 5 As shown, the initial discharge specific capacity is 125 mAh / g, and the reversible specific capacity is less than 100 mAh / g after 120 cycles.
[0052] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. A method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery, characterized in that: The method comprises the following steps: soaking the negative electrode current collector in a quaternary ammonium salt fluoriding agent, washing the negative electrode current collector after the soaking, and vacuum drying to obtain a fluorinated negative electrode current collector.
2. The method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery according to claim 1, characterized in that: The quaternary ammonium salt fluorination agent includes any one or more combinations of tetramethylammonium fluoride solution, tetraethylammonium fluoride solution and tetrabutylammonium fluoride solution.
3. The method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery according to claim 1, wherein: The negative electrode current collector is any one of an aluminum current collector, a copper current collector, a zinc current collector, a lithium-tin alloy, a silver-magnesium alloy, and a lithium-indium alloy current collector.
4. The method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery according to claim 1, wherein: The solvent of the quaternary ammonium salt fluorination reagent is tetrahydrofuran.
5. The method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery according to claim 1, wherein: The concentration of the quaternary ammonium salt fluoridation agent is 0.05-2 mol / L.
6. The method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery according to claim 1, wherein: The negative electrode current collector is immersed in the quaternary ammonium salt fluorination reagent for 1-72 hours.
7. The method for preparing a fluorinated negative electrode current collector for a negative electrode-free alkali metal battery according to claim 1, wherein: Use anhydrous ethanol to clean the negative electrode current collector.
8. A negative electrode-free alkali metal battery, characterized in that: The negative electrode-free alkali metal battery comprises a positive electrode, an electrolyte and a negative electrode current collector, and the negative electrode current collector is the fluorinated negative electrode current collector according to any one of claims 1 to 7.
9. The negative electrode-free alkali metal battery according to claim 8, characterized in that: The negative electrode-free alkali metal battery includes any one of a negative electrode-free sodium metal battery, a negative electrode-free lithium metal battery and a negative electrode-free potassium metal battery.
10. The negative electrode-free alkali metal battery according to claim 8, characterized in that: The electrolyte is an ether-based electrolyte.