A copper current collector with a three-dimensional structure coupled solid electrolyte interface phase constructed in-situ on a surface and a preparation method and application thereof

Abstract

The application provides a copper current collector with a surface in-situ constructed three-dimensional structure coupled solid electrolyte interphase and a preparation method and application thereof, and belongs to the technical field of metal anode-free batteries. The preparation method of the copper current collector with the surface in-situ constructed three-dimensional structure coupled solid electrolyte interphase comprises the following steps: (1) adding a negative ion donor material into a buffer solution to obtain an electro-etching solution; (2) assembling a three-electrode system with the pretreated copper foil as a working electrode, a saturated Ag / AgCl electrode as a reference electrode, and a carbon rod as a counter electrode, using the electro-etching solution as an electrolyte, and performing constant-current electro-etching; then taking out the copper foil, washing and drying the copper foil to obtain the copper current collector with the surface in-situ constructed three-dimensional structure coupled solid electrolyte interphase. The application focuses on the effective combination of the three-dimensional structure and the solid electrolyte interphase, realizes the three-dimensional structure coupled solid electrolyte interphase at the interface of the copper current collector by the constant-current electro-etching method, and applies the three-dimensional structure coupled solid electrolyte interphase to metal anode-free batteries, thereby providing a new strategy for the development of metal anode-free batteries.

Description

Technical Field

[0001] This invention relates to a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase in situ on the surface, its preparation method and application, belonging to the field of negative electrode-free metal battery technology. Background Technology

[0002] The low-carbon transition to replace traditional fossil fuels with new energy sources urgently requires rechargeable batteries with high energy density and high rate performance. Electrodeless metal batteries (such as lithium, sodium, and zinc batteries) have become the mainstream rechargeable battery choice for electric vehicles and grid energy storage due to their cost advantages, high energy density, and mature production systems. However, compared to ion batteries and metal batteries, electrodeless metal batteries typically exhibit poorer cycle and rate performance. This is attributed to the poor reversibility and kinetics of the metal deposition / stripping reaction at the copper current collector interface, which easily induces dendrite growth leading to short circuits and irreversible metal loss. Therefore, technological innovation and improvement are urgently needed to solve the problems faced by copper current collectors in electrodeless metal batteries and accelerate their industrialization.

[0003] To address the aforementioned issues, strategies such as electrolyte modification, the construction of three-dimensional current collectors, and the fabrication of artificial protective layers have been proposed. Among these, the construction of three-dimensional current collectors and the fabrication of artificial protective layers are considered promising solutions. Constructing a three-dimensional structure can effectively increase the specific surface area, reduce the current density on the current collector surface, and release internal stress, promoting metal deposition / stripping at the current collector interface. Applying an artificial protective layer to copper current collectors can reduce metal corrosion, lower the metal nucleation barrier, induce a uniform distribution of metal ion flux, and promote uniform deposition of metal ions on the current collector surface. However, a simple three-dimensional current collector involves direct contact between the electrolyte and the electrode, failing to fundamentally suppress side reactions such as metal / electrolyte interface corrosion. Furthermore, the fabrication of artificial protective layers often suffers from inhomogeneity and instability, and may even break or detach due to their inability to adapt to changes in ion volume. In addition, current strategies for constructing three-dimensional current collectors and artificial protective layers suffer from drawbacks such as complex processes, high preparation costs, and environmental unfriendliness.

[0004] For example, Chinese patent document CN120280498A discloses a laser-etched current collector for use in lithium metal anodes of solid-state batteries. This method uses ultraviolet picosecond laser etching to construct periodic three-dimensional concave holes on the surface of a copper current collector, effectively increasing the specific surface area of ​​the current collector. When applied to solid-state batteries, this increases peel strength and battery coulombic efficiency. While this method precisely constructs a three-dimensional current collector, the manufacturing process is complex and costly, and it cannot fundamentally suppress current collector corrosion. Chinese patent document CN120600831A discloses a modified current collector for anode-less metal batteries, its preparation method, and its application. This method utilizes an in-situ modification method to obtain a modified current collector coated with copper oxide nanomaterials. This method utilizes the idea of ​​forming an artificial protective layer in situ. The constructed artificial interface layer possesses both lithiophilicity and high ionic conductivity. However, the construction of a single artificial protective layer suffers from uncontrollable thickness, insufficient mechanical properties, and the inability to timely release stress-induced cracking during the metal ion deposition and peeling process.

[0005] Therefore, it is crucial to develop a method that combines a three-dimensional structure capable of increasing the specific surface area of ​​the copper current collector and releasing internal stress with a highly stable artificial interface protective layer that isolates the metal from direct contact with the electrolyte. However, theoretically, achieving one-step coupling between the three-dimensional structure and the solid electrolyte interphase at the copper current collector interface is contradictory. This is because the construction of the three-dimensional structure requires metal stripping, while the formation of the solid electrolyte interphase requires the deposition of metal ions. Therefore, achieving one-step coupling between the three-dimensional structure and the solid electrolyte interphase at the copper current collector interface presents a significant challenge. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface, its preparation method, and its application. This invention focuses on the effective combination of a three-dimensional structure and a solid electrolyte interface. A three-dimensional structure coupled to the solid electrolyte interface is achieved at the copper current collector interface using a constant current electro-etching method. This is then applied to a negative electrode-free metal battery, providing a new strategy for the development of negative electrode-free metal batteries.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0009] (1) Add anion donor material to the buffer solution to obtain an electro-etching solution;

[0010] (2) A three-electrode system was assembled with a pretreated copper foil as the working electrode, a saturated Ag / AgCl electrode as the reference electrode, and a carbon rod as the counter electrode. Constant current electro-etching was performed using an electro-etching solution as the electrolyte. After that, the copper foil was removed, cleaned, and dried to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface.

[0011] According to a preferred embodiment of the present invention, the buffer solution in step (1) is a sodium acetate-acetic acid buffer solution with a pH of 4.75. The sodium acetate-acetic acid buffer solution is prepared by the following method: sodium acetate and acetic acid are added to water at a molar ratio of 1:1 and stirred evenly to obtain a solution in which the concentrations of sodium acetate and acetic acid are both 0.5 mol / L.

[0012] According to a preferred embodiment of the present invention, the anion donor material in step (1) is sodium sulfide, boric acid, sodium hydrogen phosphate, sodium oxalate or sodium aluminate; the concentration of the anion donor material in the electroetching solution is 0.15-0.25 mol / L, more preferably 0.2 mol / L.

[0013] According to a preferred embodiment of the present invention, in step (2), the pretreatment method of the copper foil is as follows: ultrasonically clean the copper foil with deionized water and anhydrous ethanol for 5-10 minutes each to remove inorganic and organic impurities on the surface of the copper foil, and then vacuum dry it at 50-60°C for 6-7 hours.

[0014] According to the present invention, in step (2), electro-etching refers to etching the surface of the pretreated copper foil with electrons, specifically: applying current to the three-electrode system using a Princeton electrochemical workstation to cause a reaction on the surface of the copper foil: Cu-2e - = Cu 2+ This process etches the copper foil interface to form a three-dimensional structure. During the etching process, the unsolvated copper ions stripped off combine with the anion donors adsorbed at the copper foil / solution interface to form a solid electrolyte interphase.

[0015] According to a preferred embodiment of the present invention, the current density of the electro-etching in step (2) is 30-40 mA / cm². 2 The total capacity of the electro-etching is 4-6 mAh / cm³. 2 The total capacity of electro-etching is the amount of electricity etched per unit area under a given current density within a given time.

[0016] According to a preferred embodiment of the present invention, the cleaning in step (2) is performed by sequentially using deionized water and anhydrous ethanol; the drying is performed by drying at 50-60°C for 6-7 hours.

[0017] This invention provides a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase, which is constructed in situ on the surface and prepared using the above-described method.

[0018] According to the present invention, the copper current collector with the above-mentioned surface in-situ constructed three-dimensional structure coupled with the solid electrolyte interphase is used as a current collector in a negative electrode-free metal battery, which includes, but is not limited to, a negative electrode-free zinc battery, a negative electrode-free lithium battery, or a negative electrode-free sodium battery.

[0019] In this invention, room temperature has a meaning known in the art, referring to 25±5℃.

[0020] The working principle of this invention, which involves in-situ construction of a three-dimensional structure coupled with a solid electrolyte interphase at the copper current collector interface, is as follows:

[0021] When copper foil comes into contact with the electro-etching solution, an electrical double layer is formed on its electrode / electrolyte surface, specifically including a Helmholtz layer and a diffusion layer. The Helmholtz layer further includes an inner Helmholtz layer and an outer Helmholtz layer. The inner Helmholtz layer consists of specifically adsorbed anions and polar water molecules, while the outer Helmholtz layer is generally composed of solvated ions. The diffusion layer is a region where various anions, cations, and water molecules are randomly distributed. When a bias current is applied, the copper foil surface is etched to form a three-dimensional structure. At the same time, the unsolvated copper ions that have lost electrons combine with anion donors (such as sulfide ions, phosphate ions, etc.) and form solid electrolyte nuclei in situ at the three-dimensional structure sites formed by the etching. Subsequently, under the influence of the electric field, more anions move to the copper foil side, and the solid electrolyte nuclei gradually form a uniform solid electrolyte layer, eventually forming a solid electrolyte interface phase in situ at the three-dimensional structure interface.

[0022] The technical features and beneficial effects of this invention are as follows:

[0023] 1. This invention uses electrons as an etchant. Compared with other etching methods such as acid etching, alkaline etching, and other gas phase and solid phase etching methods, the etchant of this invention uses green and pollution-free electrons, and the etchant utilization rate is as high as 100%. Moreover, as a mild etchant, electrons can effectively control the degree of etching, making the three-dimensional etched structure on the copper foil surface more uniform, oriented, and controllable.

[0024] 2. The electro-etching solution system of the present invention is green and recyclable. By adding anion donor material to the electro-etching solution after electro-etching, the electro-etching solution can be reused.

[0025] 3. This invention forms a three-dimensional structure on the surface of copper foil while simultaneously generating a uniform and stable solid electrolyte interfacial phase in situ at its interface. The two work synergistically: Firstly, the three-dimensional structure increases the specific surface area of ​​the copper foil, reducing internal stress and current density, and minimizing dendrite formation. However, the copper foil with a simple three-dimensional structure is still in direct contact with the electrolyte, failing to fundamentally solve corrosion and side reactions. The in-situ grown solid electrolyte interfacial phase isolates the three-dimensional structure from the electrolyte, fundamentally mitigating the reduction in battery life caused by copper foil corrosion. Secondly, the solid electrolyte interfacial phase effectively reduces corrosion on the copper foil surface and improves ion transport efficiency. However, traditional two-dimensional solid electrolyte interfacial phases are prone to detachment or breakage during the continuous insertion / extraction of metal ions. The construction of the three-dimensional structure effectively releases internal stress and enhances the stability of the solid electrolyte interfacial phase. This "two birds with one stone" strategy of coupling the three-dimensional structure with the in-situ grown solid electrolyte interfacial phase effectively overcomes problems such as dendrite formation and side reactions in the negative electrode current collector of electrodeless metal batteries. The synergistic effect of both contributes to extending the cycle stability of electrodeless metal batteries, providing a new strategy for their development. Attached Figure Description

[0026] Figure 1 Scanning electron microscope images of the copper current collectors prepared in Examples 1-5.

[0027] Figure 2 EDX spectra of the copper current collectors prepared in Examples 1-5.

[0028] Figure 3 The contact angle between the copper current collector and the electrolyte prepared in Examples 1-5 is shown.

[0029] Figure 4 Cycle performance of the negative electrode-free metal batteries assembled with copper current collectors prepared in Example 1 and Comparative Examples 1 and 2.

[0030] Figure 5 Cycle performance of the negative electrode-free metal batteries assembled with copper current collectors prepared in Comparative Examples 3-7. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. It should be noted that the specific embodiments described are illustrative of the invention and not limiting.

[0032] Unless otherwise specified, all reagents and instruments used are commercially available products. Experiments not specifying particular conditions were conducted under standard conditions. All other experimental examples obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0033] The pretreatment method for copper foil in the examples and comparative examples is as follows: the copper foil is ultrasonically cleaned for 10 minutes each with deionized water and anhydrous ethanol to remove inorganic and organic impurities from the surface of the copper foil, and then dried in a vacuum oven at 60°C for 6 hours.

[0034] The sodium acetate-acetic acid buffer solution used in the examples and comparative examples was prepared by the following method: sodium acetate and acetic acid were added to water at a molar ratio of 1:1 and stirred until homogeneous to obtain the sodium acetate-acetic acid buffer solution. The concentrations of sodium acetate and acetic acid in the sodium acetate-acetic acid buffer solution were both 0.5 mol / L, and the pH of the solution was 4.75.

[0035] Example 1

[0036] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0037] (1) At room temperature, sodium sulfide was added to sodium acetate-acetic acid buffer solution to obtain an electro-etching solution a containing sodium sulfide at a concentration of 0.2 mol / L.

[0038] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution a.

[0039] (3) Apply 30 mA / cm using a Princeton electrochemical workstation 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0040] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface, denoted as 3D Cu@CuS.

[0041] Example 2

[0042] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0043] (1) At room temperature, sodium hydrogen phosphate was added to sodium acetate-acetic acid buffer solution to obtain an electro-etching solution b containing sodium hydrogen phosphate at a concentration of 0.2 mol / L.

[0044] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution b.

[0045] (3) Apply 30 mA / cm using a Princeton electrochemical workstation 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0046] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface, denoted as 3D Cu@CuPO.

[0047] Example 3

[0048] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0049] (1) At room temperature, boric acid was added to sodium acetate-acetic acid buffer solution to obtain an electro-etching solution c with a concentration of 0.2 mol / L.

[0050] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution c.

[0051] (3) Apply 30 mA / cm using a Princeton electrochemical workstation 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0052] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface, denoted as 3D Cu@CuBO.

[0053] Example 4

[0054] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0055] (1) At room temperature, sodium oxalate was added to sodium acetate-acetic acid buffer solution to obtain an electroetching solution d with a concentration of 0.2 mol / L.

[0056] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution d.

[0057] (3) Apply 30 mA / cm using a Princeton electrochemical workstation2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0058] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface, denoted as 3D Cu@CuCO.

[0059] Example 5

[0060] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0061] (1) At room temperature, sodium aluminate was added to sodium acetate-acetic acid buffer solution to obtain an electroetching solution e with a concentration of 0.2 mol / L.

[0062] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution e.

[0063] (3) Apply 30 mA / cm using a Princeton electrochemical workstation 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0064] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface, which is denoted as 3D Cu@CuAlO.

[0065] Comparative Example 1

[0066] Pretreated copper foil is used as the copper current collector, denoted as Cu.

[0067] Comparative Example 2

[0068] A method for preparing a three-dimensional copper current collector includes the following steps:

[0069] (1) At room temperature, sodium acetate-acetic acid buffer solution is used directly as the electroetching solution f.

[0070] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution f.

[0071] (3) Apply 30 mA / cm using a Princeton electrochemical workstation 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0072] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a three-dimensional copper current collector, denoted as 3D Cu.

[0073] Comparative Example 3

[0074] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0075] (1) At room temperature, sodium sulfide was added to sodium acetate-acetic acid buffer solution to obtain g of electro-etching solution containing sodium sulfide concentration of 2 mol / L.

[0076] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution g.

[0077] (3) Apply 30 mA / cm using a Princeton electrochemical workstation 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0078] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to the solid electrolyte interface phase in situ on the surface, which is denoted as 3D Cu@CuS (2mol / L sodium sulfide).

[0079] Comparative Example 4

[0080] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface includes the following steps:

[0081] (1) At room temperature, sodium sulfide was added to sodium acetate-acetic acid buffer solution to obtain an electro-etching solution h containing sodium sulfide with a concentration of 0.02 mol / L.

[0082] (2) Assemble a three-electrode system with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode and carbon rod as the counter electrode, and place it in an electro-etching device containing electro-etching solution h.

[0083] (3) Apply 30 mA / cm using a Princeton electrochemical workstation2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 .

[0084] (4) Take out the copper foil and clean it with deionized water and anhydrous ethanol in sequence to remove the soluble ions and impurities remaining on the surface. Then, vacuum dry it at 60°C for 6 hours to obtain a copper current collector with a three-dimensional structure coupled to the solid electrolyte interface phase in situ on the surface, denoted as 3D Cu@CuS (0.02mol / L sodium sulfide).

[0085] Comparative Example 5

[0086] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface is as described in Example 1, except that: in step (3), 300 mA / cm 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 A copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase was obtained by in-situ construction on the surface, denoted as 3D Cu@CuS (300 mA / cm). 2 ).

[0087] Comparative Example 6

[0088] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface is as described in Example 1, except that: in step (3), 3 mA / cm 2 Constant current electro-etching was performed, and the total etching capacity was 5 mAh / cm². 2 A copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase was obtained by in-situ construction on the surface, denoted as 3D Cu@CuS (3mA / cm). 2 ).

[0089] Comparative Example 7

[0090] A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase in situ on the surface is described in Example 1, except that: in step (1), deionized water is used instead of sodium acetate-acetic acid buffer solution, and the pH of the system is adjusted to 4.75 using 3 mol / L hydrochloric acid aqueous solution to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase in situ on the surface, denoted as 3D Cu@CuS (deionized water).

[0091] Experimental Example 1

[0092] The copper current collectors prepared in Examples 1-5 were characterized.

[0093] Figure 1 Scanning electron microscope (SEM) images of the copper current collectors prepared in Examples 1-5. Figure 1It can be seen that the interfaces of the five copper current collectors all form relatively uniform aperiodic three-dimensional structures. Although the three-dimensional structures are different, they share common features: they all contain micron-level unevenness and are covered with pores and grooves. The SEI nuclei are clearly visible at the 3D Cu@CuPO, 3D Cu@CuCO, and 3D Cu@AlO interfaces. Pores and grooves are observed in the micron-level uneven three-dimensional structure, and a uniform SEI film is visible inside. The 3D Cu@CuBO interface shows plate-like SEI containing aperiodic pores and grooves. The three-dimensional structure of the 3D Cu@CuS interface is distributed in an aperiodic grid pattern, containing a large number of pores and grooves, and a uniform SEI film is visible inside.

[0094] Figure 2 The EDX spectra of the copper current collectors prepared in Examples 1-5 are shown. The EDX spectra indicate that the copper current collector interface contains a uniform SEI element distribution, proving the successful formation of the SEI.

[0095] Figure 3 The figures show the contact angles of the copper current collectors prepared in Examples 1-5 and the copper current collector in Comparative Example 1 with the electrolyte. Bare copper has a large contact angle with the electrolyte, exhibiting poor electrolyte wettability. This leads to slow ion transport efficiency, severe concentration polarization, promotes dendrite formation, and significantly reduces battery life. 3D Cu@CuPO, 3D Cu@CuCO, and 3D Cu@AlO have smaller contact angles with the electrolyte, demonstrating that the high specific surface area three-dimensional structure coupled with the SEI can alleviate interfacial ion polarization and promote uniform deposition and stripping of metal ions. 3D Cu@CuBO and 3DCu@CuS have extremely small contact angles with the electrolyte; their superior electrolyte wettability increases effective contact at the electrode interface, improves charge transfer efficiency, inhibits dendrite growth, and enhances battery life.

[0096] Experimental Example 2

[0097] Using the copper current collector prepared in the examples and comparative examples as the negative electrode, a Cu||LiMn2O4 negative electrode-free metal battery was assembled in the following order: CR2032 positive electrode shell, LiMn2O4 positive electrode, glass fiber separator (Whatman GF / F, UK), 100uL electrolyte, copper current collector, nickel foam, and CR2032 negative electrode shell. The electrolyte was an aqueous solution containing 2mol / L lithium sulfate and 1mol / L zinc sulfate.

[0098] Cycle performance was measured using the Cu||LiMn2O4 electrodeless metal battery assembled in the examples, with the electrodeless metal battery from the comparative examples used for comparison. Tests were conducted at 0.5C, and the results are as follows: Figure 4-5 As shown. In Comparative Example 1, the capacity of the metal-free battery without a negative electrode decreased to 13 mAh g after 50 cycles. -1The capacity retention rate was only 15%, which can be attributed to severe dendrite growth and the accumulation of by-reaction products on the zinc surface, preventing normal zinc ion stripping and deposition. In Comparative Example 2, the capacity retention rate of the electrodeless metal battery increased slightly to 51% after 50 cycles, demonstrating the promoting effect of the three-dimensional structure on battery cycling. However, the three-dimensional structure alone cannot fundamentally suppress the occurrence of by-reactions. The electrodeless metal batteries in Examples 1-5 maintained higher capacity and more stable cycling under 0.5C conditions, with the 3D Cu@CuS capacity retention rate reaching 96%, demonstrating the good coupling between the three-dimensional structure of the modified copper current collector and the solid electrolyte layer. Comparative Examples 3 and 4 showed similar specific capacities under 0.5C conditions, with 3DCu@CuS (2mol / L) exhibiting a more stable coulombic efficiency, indicating that 3DCu@CuS can be generated under both concentrations of sodium sulfide. The difference in coulombic efficiency can be attributed to the different thicknesses of the SEI (CuS). Comparative Examples 5 and 6 investigated the effect of different currents on the performance of 3DCu@CuS electro-etched cells without anodes. The results showed that excessive current (300 mA / cm²) was detrimental to the performance of the cells. 2 ) or too small (3mA / cm 2 Both current and current density (30 mA / cm²) will reduce the performance of the negative electrode-free metal battery. This is attributed to the excessively fast etching rate under high current, which leads to microfractures in the generated SEI; while lower current lacks sufficient driving force for SEI nucleation and cannot form a uniform and stable SEI. Therefore, a moderate current density (30 mA / cm²) is selected. 2 The optimal 3D Cu@CuS can be obtained. Comparative Example 7 investigated the effect of buffer solution on the electro-etching system. The results showed that 3D Cu@CuS prepared under conditions lacking buffer solution had a certain impact on the anode-free metal battery, reducing the physical and chemical properties of the electrode and thus lowering the performance of the anode-free metal battery. Therefore, adding buffer solution to the electro-etching solution can maintain the directional and controllable formation of SEI, thereby better improving the performance of the anode-free metal battery.

Claims

1. A method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase constructed in situ on the surface, characterized in that, The steps include the following: (1) An anion donor material is added to a buffer solution to obtain an electro-etching solution; the buffer solution is a sodium acetate-acetic acid buffer solution with a pH of 4.75 and a concentration of 0.5 mol / L for both sodium acetate and acetic acid in the sodium acetate-acetic acid buffer solution; the anion donor material is sodium sulfide, boric acid, sodium hydrogen phosphate, sodium oxalate, or sodium aluminate; the concentration of the anion donor material in the electro-etching solution is 0.15-0.25 mol / L; (2) A three-electrode system was assembled with pretreated copper foil as the working electrode, saturated Ag / AgCl electrode as the reference electrode, and carbon rod as the counter electrode. Constant current electro-etching was performed using an electro-etching solution as the electrolyte. The copper foil was then removed, cleaned, and dried to obtain a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface; the current density of the electro-etching was 30-40 mA / cm². 2 The total capacity of the electro-etching is 4-6 mAh / cm³. 2 .

2. The method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface according to claim 1, characterized in that, The sodium acetate-acetic acid buffer solution described in step (1) is prepared by the following method: sodium acetate and acetic acid are added to water at a molar ratio of 1:1 and stirred until homogeneous.

3. The method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase constructed in situ on the surface according to claim 1, characterized in that, The concentration of the anion donor material in the electro-etching solution in step (1) is 0.2 mol / L.

4. The method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface according to claim 1, characterized in that, In step (2), the pretreatment method for copper foil is as follows: ultrasonically clean it with deionized water and anhydrous ethanol for 5-10 minutes each, and then vacuum dry it at 50-60℃ for 6-7 hours.

5. The method for preparing a copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase constructed in situ on the surface according to claim 1, characterized in that, The cleaning in step (2) involves sequentially cleaning with deionized water and anhydrous ethanol; the drying involves drying at 50-60℃ for 6-7 hours.

6. A copper current collector with a three-dimensional structure coupled to a solid electrolyte interphase in situ on its surface, characterized in that, It is prepared by the preparation method described in any one of claims 1-5.

7. The application of the copper current collector with a three-dimensional structure coupled to a solid electrolyte interface phase in situ on the surface as described in claim 6, characterized in that... As a current collector, it is used in electrodeless metal batteries, including electrodeless zinc batteries, electrodeless lithium batteries, or electrodeless sodium batteries.

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