Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure as well as preparation method and application of Cu3Sn / Cu6Sn5 composite electrode

Abstract

The invention provides a Cu3Sn / Cu6Sn5 composite electrode with a nano-porous structure as well as a preparation method and application of the Cu3Sn / Cu6Sn5 composite electrode. The preparation method comprises the following steps: removing surface oxide layers of copper and tin metal sheets and aluminum metal wires, weighing copper, tin and aluminum, smelting to obtain an alloy ingot, cutting the alloy ingot into metal sheets, removing surface oxide layers of the metal sheets, and putting the metal sheets into a KOH solution for dealloying treatment to prepare the Cu3Sn / Cu6Sn5 composite electrode with the nano-porous structure. The electrode is composed of two intermetallic compounds of Cu3Sn and Cu6Sn5, has a hierarchical porous structure, and comprises a macroporous channel with the pore diameter of 100-400 nm and mesopores with the pore diameter of 5-50 nm distributed on a macroporous ligament. The hierarchical porous structure of the composite electrode and efficient charge transfer at a heterogeneous interface can effectively reduce local current density, guide zinc ions to uniformly deposit, inhibit dendritic crystal growth and improve reaction kinetics and structural stability, the composite electrode is applied to an aqueous zinc ion battery as a negative electrode, and the service life of the aqueous zinc ion battery is prolonged. The cycle life and the rate capability of the battery can be obviously improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water-based zinc ion battery electrode materials, and particularly relates to a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure and a preparation method and application thereof. BACKGROUND

[0002] With the continuous growth of global energy demand, the use of clean and renewable energy is expanding. However, clean energy such as wind and solar energy has problems such as intermittency and volatility, and it is urgent to develop high-efficiency and stable energy storage systems to realize stable grid connection and large-scale application. At present, although lithium ion batteries are widely used, they are subject to the dual constraints of limited lithium resources and safety hazards of organic electrolyte, which promotes the exploration of new energy storage systems. In the multi-valence metal ion battery system, each metal ion (Mg 2+ , Ca 2+ , Zn 2+ , Al 3+ ) can transfer two or more electrons in the electrochemical reaction, and has a high theoretical energy density, so it is considered as a strong candidate for the next generation of energy storage technology. Among them, water-based zinc ion batteries use relatively safe water-based electrolyte, and have the potential for large-scale application due to abundant resources and simple assembly process.

[0003] Compared with lithium ion batteries, water-based zinc ion batteries exhibit significant advantages in cost, safety and environmental friendliness. The zinc negative electrode has a suitable redox potential (-0.76V vs SHE) and a high theoretical capacity (820mAhg -1 and 5855mAh cm -3 ), and the non-flammable water-based electrolyte fundamentally eliminates the inherent flammable and explosive safety hazards of the organic system. However, the commercial application of water-based zinc ion batteries is still limited by a series of problems in the negative electrode interface, mainly including uncontrollable dendrite growth, hydrogen evolution side reactions and electrode corrosion. These problems can cause the battery cycle life to deteriorate rapidly and seriously affect its actual service life, and thus become the main obstacle to the commercial application of water-based zinc ion batteries. To address the above challenges, designing and preparing new negative electrode materials and establishing an efficient and reversible zinc deposition / stripping process on the negative electrode side are the key to improving the practical application of water-based zinc ion batteries.

[0004] The Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure is obtained by chemical dealloying treatment of copper, tin and aluminum alloy by controlling temperature and time. The three-dimensional porous structure can significantly increase the specific surface area of the electrode, thereby reducing the local current density of the electrode and the nucleation overpotential of zinc ion deposition. Meanwhile, the high-efficiency charge transfer at the heterogeneous interface can effectively guide the reversible and dendrite-free zinc deposition / strip behavior. With the synergistic effect of reversible component conversion and porous structure, it is possible to mass-produce the aqueous zinc ion battery negative electrode which can be stably cycled for a long time. SUMMARY

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the present disclosure provides a Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure and a preparation method and application thereof.

[0006] According to a first aspect of the present application, a preparation method of a Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure is provided, comprising the following steps:

[0007] 1) removing the surface oxide layer of copper, tin metal sheets and aluminum metal wires, and weighing the copper, tin and aluminum metals according to the atomic ratio of 15:15:70 respectively;

[0008] 2) placing the weighed copper, tin and aluminum metals into a vacuum arc melting furnace under argon protection to obtain a precursor alloy ingot with uniform alloy composition;

[0009] 3) cutting the alloy ingot into a metal sheet with a thickness of 400 μm on a diamond wire cutting machine, and removing the surface oxide layer of the metal sheet;

[0010] 4) placing the metal sheet in a KOH solution for dealloying treatment at a preset temperature to obtain a Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure.

[0011] According to a second aspect of the present application, a Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure is provided. The Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure has a hierarchical porous structure composed of macroporous channels and mesopores distributed on the macroporous ligament. The macroporous structure is derived from the dealloying treatment of the Al phase in the precursor, and the mesopores are formed by selective dissolution of Al in the Al2Cu phase and uniformly distributed on the surface of the macroporous ligament. The macropore diameter ranges from 100 nm to 400 nm, and the mesopore diameter ranges from 5 nm to 50 nm.

[0012] According to a third aspect of the present application, the application of a Cu3Sn / Cu6Sn5 composite electrode with nano-porous structure is provided. The composite electrode is used as the negative electrode of an aqueous zinc ion battery to assemble an aqueous zinc ion battery.

[0013] The purpose of this invention is to synergistically introduce copper and tin elements and construct a self-supporting nanoporous structure, proposing a Cu3Sn / Cu6Sn5 composite electrode material with a nanoporous structure for use as the anode in aqueous zinc-ion batteries. This electrode uses Cu3Sn and Cu6Sn5 intermetallic compounds as the matrix and possesses a hierarchical porous structure, consisting of macropores and mesopores distributed on the macropore ligaments. The macropore structure is formed by dealloying the Al phase in the precursor, with a pore size ranging from 100-400 nm; the mesopores are formed by the selective dissolution of Al from the Al2Cu phase and are uniformly distributed on the surface of the macropore ligaments, with a pore size ranging from 5-50 nm.

[0014] The beneficial effects of this invention are:

[0015] This invention provides a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure that is simple to prepare and has a reasonable structural design. This composite electrode achieves synergistic optimization of material performance through integrated control of composition and structure. Specifically, the composite electrode possesses a hierarchical porous structure composed of zinc-loving Cu3Sn and Cu6Sn5 intermetallic compounds, which can effectively reduce the nucleation overpotential of zinc and homogenize the local current density, thereby suppressing side reactions and promoting highly reversible zinc deposition / stripping. Compared with pure zinc electrodes, symmetric and full cells assembled based on the nanoporous Cu3Sn / Cu6Sn5 composite electrode show significant improvements in electrochemical activity, structural stability, and cycle life. This invention not only provides a new design concept for zinc-ion battery anode materials but also offers a feasible technical path for achieving high-performance, long-life aqueous zinc-ion batteries. Attached Figure Description

[0016] Figure 1 Scanning electron microscope (SEM) image of a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure;

[0017] Figure 2 Energy dispersive X-ray spectroscopy (EDS) of Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure;

[0018] Figure 3 X-ray diffraction (XRD) pattern of Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure;

[0019] Figure 4 Nucleation overpotential curves (voltage-time curves) of Cu3Sn / Cu6Sn5 composite electrodes with nanoporous structures;

[0020] Figure 5Electrochemical impedance spectroscopy (EIS) of a standard symmetric cell assembled with a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure;

[0021] Figure 6 Tafel curves of a standard symmetric cell assembled with a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure.

[0022] Figure 7 A standard symmetrical cell was assembled using a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure, achieving a current density of 1 mA / cm². -2 Surface capacity is 1mAh cm -2 The long-cycle stability test curves (voltage-time curves) under the given conditions;

[0023] Figure 8 Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure and Zn supported on carbon cloth x A standard aqueous zinc-ion full cell assembled with a V₂O₅ electrode achieves a voltage of 0.2 mV / s. -1 Cyclic voltammetry (CV) curves at scan rate;

[0024] Figure 9 Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure and Zn supported on carbon cloth x Electrochemical impedance spectroscopy (EIS) of a standard aqueous zinc-ion full cell assembled with a V2O5 electrode;

[0025] Figure 10 Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure and Zn supported on carbon cloth x A standard aqueous zinc-ion full cell assembled with a V₂O₅ electrode operates at 0.2–10 A g. -1 Rate performance test curves within the current density range;

[0026] Figure 11 Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure and Zn supported on carbon cloth x A standard aqueous zinc-ion full cell is assembled using a V₂O₅ electrode at a capacity of 0.5 Ag. -1 Charge-discharge cycle test curves at current densities;

[0027] Figure 12 Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure and Zn supported on carbon cloth x A standard aqueous zinc-ion full cell with V2O5 electrode assembly at 10Ag -1 Charge-discharge cycle test curves at current densities. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] The preparation method of the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure of the present invention includes the following specific steps:

[0031] Step 1: Soak and clean copper and tin metal sheets in 80mM dilute hydrochloric acid solution to remove the surface oxide layer. Soak and clean aluminum metal wire in 60mM dilute KOH solution to remove the surface oxide layer. Rinse the metal surface with ultrapure water multiple times to remove residual dilute hydrochloric acid and dilute KOH solution. Place the cleaned metal in a vacuum drying oven and dry at room temperature for about 8 hours.

[0032] Step 2: Weigh the dried copper, tin, and aluminum metals from Step 1 according to an atomic ratio of 15:15:70. Weigh 3.09g of copper sheet, 5.78g of tin sheet, and 6.13g of aluminum wire. Place the weighed copper, tin, and aluminum metals in a vacuum arc melting furnace and melt them under an argon atmosphere. Melt them 5 times, then flip them over and melt them 5 more times to ensure that the three metal components are mixed evenly and a homogeneous alloy is obtained. After cooling in the furnace, remove the alloy ingot. Its composition by atomic percentage is Cu. 15 Sn 15 Al 70 ;

[0033] Step 3: Use a diamond wire cutter to cut the smelted Cu 15 Sn 15 Al 70 The alloy ingot was cut into metal sheets with a thickness of 400 μm, and the oxide layer on the surface of the metal sheets was removed by polishing to obtain Cu with a thickness of 200 μm. 15 Sn 15 Al 70 Metal sheet;

[0034] Step 4: Add Cu 15 Sn 15 Al 70 The metal sheet was placed in a 6M KOH solution and subjected to a dealloying treatment at 90°C for 5 hours. The Cu after the dealloying treatment was then rinsed multiple times with ultrapure water. 15 Sn 15 Al 70The metal sheet, after removing the residual KOH solution from its surface, is placed in a vacuum drying oven and dried at room temperature for 8 hours to obtain a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure. This electrode can be used as the negative electrode of an aqueous zinc-ion battery.

[0035] Example 2

[0036] Step 1: Soak and clean copper and tin metal sheets in 80mM dilute hydrochloric acid solution to remove the surface oxide layer. Soak and clean aluminum metal wire in 60mM dilute KOH solution to remove the surface oxide layer. Rinse the metal surface with ultrapure water multiple times to remove residual dilute hydrochloric acid and dilute KOH solution. Place the cleaned metal in a vacuum drying oven and dry at room temperature for about 8 hours.

[0037] Step 2: Weigh the dried copper, tin, and aluminum metals from Step 1 according to an atomic ratio of 27:3:70. Weigh 6.50g of copper sheet, 1.35g of tin sheet, and 7.15g of aluminum wire. Place the weighed copper, tin, and aluminum metals in a vacuum arc melting furnace and melt them under an argon atmosphere. Melt them 5 times, then flip them over and melt them 5 more times to ensure that the three metal components are mixed evenly and to obtain a homogeneous alloy. After cooling in the furnace, remove the alloy ingot. Its composition by atomic percentage is Cu. 27 Sn3Al 70 ;

[0038] Step 3: Use a diamond wire cutter to cut the smelted Cu 27 Sn3Al 70 The alloy ingot was cut into metal sheets with a thickness of 400 μm, and the oxide layer on the surface of the metal sheets was removed by polishing to obtain Cu with a thickness of 200 μm. 27 Sn3Al 70 Metal sheet;

[0039] Step 4: Add Cu 27 Sn3Al 70 The metal sheet was placed in a 6M KOH solution and subjected to a dealloying treatment at 90°C for 5 hours. The Cu after the dealloying treatment was then rinsed multiple times with ultrapure water. 27 Sn3Al 70 The metal sheet, after removing the residual KOH solution from its surface, is placed in a vacuum drying oven and dried at room temperature for 8 hours to obtain a Cu3Sn / Cu composite electrode with a nanoporous structure. This electrode can be used as the negative electrode of an aqueous zinc-ion battery.

[0040] Example 3

[0041] Step 1: Soak and clean copper and tin metal sheets in 60mM dilute hydrochloric acid solution to remove the surface oxide layer. Soak and clean aluminum metal wire in 80mM dilute KOH solution to remove the surface oxide layer. Rinse the metal surface multiple times with ultrapure water to remove residual dilute hydrochloric acid and dilute KOH solution. Place the cleaned metal in a vacuum drying oven and dry at room temperature for about 8 hours.

[0042] Step 2: Weigh the dried copper, tin, and aluminum metals from Step 1 according to an atomic ratio of 10:20:70. Weigh 1.95g of copper sheet, 7.27g of tin sheet, and 5.78g of aluminum wire. Place the weighed copper, tin, and aluminum metals in a vacuum arc melting furnace and melt them under an argon atmosphere. Melt them 5 times, then flip them over and melt them 5 more times to ensure that the three metal components are mixed evenly and a homogeneous alloy is obtained. After cooling in the furnace, remove the alloy ingot. Its composition by atomic percentage is Cu. 10 Sn 20 Al 70 ;

[0043] Step 3: Use a diamond wire cutter to cut the smelted Cu 10 Sn 20 Al 70 The alloy ingot was cut into metal sheets with a thickness of 400 μm, and the oxide layer on the surface of the metal sheets was removed by polishing to obtain Cu with a thickness of 200 μm. 10 Sn 20 Al 70 Metal sheet;

[0044] Step 4: Add Cu 10 Sn 20 Al 70 The metal sheet was placed in a 6M KOH solution and subjected to a dealloying treatment at 90°C for 5 hours. The Cu after the dealloying treatment was then rinsed multiple times with ultrapure water. 10 Sn 20 Al 70 Metal sheets, after removing residual KOH solution from their surface, are placed in a vacuum drying oven and dried at room temperature for 8 hours to obtain a Cu6Sn5 / Sn composite electrode with a nanoporous structure. This electrode can be used as the negative electrode of an aqueous zinc-ion battery.

[0045] Comparative Example 1

[0046] To compare the electrochemical performance differences between the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure described in this invention and a pure zinc electrode, a commercially available high-purity zinc sheet was used as a comparative electrode. The pure zinc electrode was polished before electrochemical performance testing.

[0047] Morphological and structural characterization of materials:

[0048] The dealloyed samples were characterized using scanning electron microscopy (SEM), and the results are as follows: Figure 1 As shown, this Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure exhibits a clear hierarchical porous structure, demonstrating that the composite electrode sample possesses macropore channels and uniformly distributed mesopores on the macropore ligaments. The macropore diameter ranges from 100 to 400 nm, and the mesopore diameter ranges from 5 to 50 nm. The structure of this composite electrode provides ion diffusion channels and effectively increases the specific surface area of ​​the electrode, thereby facilitating ion transport. Figure 2 The EDS spectrum shown indicates that the atomic ratio of copper, tin, and aluminum in the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure is approximately 71:26:3. Figure 3 The XRD pattern confirmed that the electrode is mainly composed of two intermetallic compounds, Cu3Sn and Cu6Sn5, and the Al phase in the precursor and the Al in the Al2Cu phase have been effectively removed by selective corrosion.

[0049] Electrochemical performance characterization results of the material:

[0050] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was used as the working electrode, and the electrolyte was 1 mol L⁻¹. -1 Zn(OTf)2 was dissolved in a mixed solution of water / diethylene glycol dimethyl ether (volume ratio 2:1) to form a standard symmetrical cell and electrochemical tests were performed.

[0051] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was subjected to a 1 mA cm⁻¹ test. -2 Nucleation overpotential tests were performed at current densities;

[0052] The Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure prepared in Example 1 was assembled into a symmetrical cell and subjected to electrochemical impedance spectroscopy (EIS) in the frequency range of 100 kHz to 10 mHz.

[0053] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was used to assemble a symmetric cell at 1 mV s. -1 The scan rate was tested using Tafel.

[0054] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was assembled into a symmetrical cell and subjected to a 1 mA cm⁻¹ test. -2 Current density, 1mAh cm -2 Long-term cycling stability tests were conducted at the areal capacity.

[0055] Using the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 as the negative electrode, and Zn supported on carbon cloth... x Using V2O5 electrode as the positive electrode, with 1 mol L -1 A standard aqueous zinc-ion full cell was assembled using a mixed solution of Zn(OTf)2 dissolved in water / diethylene glycol dimethyl ether (volume ratio 2:1) as the electrolyte and electrochemical tests were conducted.

[0056] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was combined with Zn supported on carbon cloth. x Aqueous zinc-ion full cells assembled with V₂O₅ electrodes achieve a voltage of 0.2 mV / s. -1 The scan rate was tested using cyclic voltammetry (CV).

[0057] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was combined with Zn supported on carbon cloth. x Electrochemical impedance spectroscopy (EIS) was performed on aqueous zinc-ion full cells assembled with V2O5 electrodes in the frequency range of 100 kHz to 10 mHz.

[0058] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was combined with Zn supported on carbon cloth. x Aqueous zinc-ion full cells assembled with V₂O₅ electrodes operate within the 0.2–10 Ag⁻¹ range. -1 Rate performance testing was conducted within the current density range;

[0059] The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure prepared in Example 1 was combined with Zn supported on carbon cloth. x Aqueous zinc-ion full cells assembled with V₂O₅ electrodes were used at 0.5 Ag⁻¹. -1 and 10Ag -1 Charge-discharge cycle tests were conducted at a current density of [value missing].

[0060] like Figure 4 As shown in the voltage-time curve, the Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure of the present invention exhibits an extremely low nucleation overpotential (approximately 0.66 mV), indicating that it has good zinc affinity and can significantly reduce the energy barrier during the electrochemical deposition process, promoting the nucleation and deposition of zinc ions. Figure 5This paper compares the electrochemical impedance spectroscopy (EIS) of a symmetric cell assembled using the nanoporous Cu3Sn / Cu6Sn5 composite electrode of this invention with that of a pure zinc electrode. The charge transfer resistance of the symmetric cell using the nanoporous Cu3Sn / Cu6Sn5 composite electrode of this invention is approximately 7.5 Ω, while the charge transfer resistance of the pure zinc symmetric cell is approximately 331 Ω. This indicates that the composite electrode effectively improves the electrochemical activity and interfacial reaction kinetics compared to the pure zinc electrode. Figure 6 The Tafel curve shows that the corrosion potential of the Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure of the present invention is -3mV, which is significantly positively shifted compared with the pure zinc electrode (-18mV), indicating that it has better corrosion resistance. Figure 7 This demonstrates the symmetrical cell at 1 mA cm -2 1mAh cm -2 The results of long-term cycling stability tests under the specified conditions. The Cu3Sn / Cu6Sn5 composite electrode symmetric cell with nanoporous structure of the present invention did not show significant polarization increase or short circuit phenomenon during more than 7500 hours of cycling. In contrast, the pure zinc symmetric cell showed significant voltage hysteresis during the test time of about 160 hours. Figure 8 The present invention relates to a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure and Zn supported on carbon cloth. x The full cell assembled with V₂O₅ electrodes exhibited a voltage range of 0.2–1.6 V and a s0.2 mVs. -1 Cyclic voltammetry curves at the scan rate. Reduction peaks appear at 0.43V and 0.92V, and oxidation peaks appear at 0.68V and 1.14V, indicating that the battery has a highly reversible redox reaction process. Figure 9 This paper compares the electrochemical impedance spectroscopy (EIS) spectra of a full cell using the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure and a full cell using a pure zinc electrode, based on the present invention. The charge transfer resistance of the full cell using the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure is approximately 8.6 Ω, while the charge transfer resistance of the full cell using the pure zinc electrode is as high as approximately 240 Ω, further demonstrating that the composite electrode helps to improve the reaction kinetics of the battery. Figure 10 The table shows the rate performance comparison curves of the Cu3Sn / Cu6Sn5 composite electrode full cell with nanoporous structure and the pure zinc electrode full cell of this invention. The results show that, at all tested current densities, the discharge capacity of the Cu3Sn / Cu6Sn5 composite electrode full cell with nanoporous structure is significantly higher than that of the pure zinc electrode full cell. Figure 11 and Figure 12 The full cells of the Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure and the full cells of the pure zinc electrode of the present invention were respectively tested at 0.5 Ag. -1 and 10Ag -1The cycle curves of charge-discharge cycle tests were obtained at a current density of 0.5 Ag. -1 After 300 cycles, the specific capacity of the Cu3Sn / Cu6Sn5 composite electrode full cell with nanoporous structure of the present invention remains at approximately 299 mAh g⁻¹. -1 The coulombic efficiency is approximately 99.9%; while the capacity of the pure zinc electrode full cell decreases to approximately 114 mAh g after 40 charge-discharge cycles. -1 Coulomb efficiency drops to approximately 97%. At 10A g -1 Under high current, the Cu3Sn / Cu6Sn5 composite electrode with nanoporous structure of this invention retains a capacity of approximately 126 mAh g after 3500 cycles. -1 This is significantly higher than the capacity of a pure zinc electrode full cell after 500 cycles (approximately 41 mAh g). -1 The results demonstrate that the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure significantly improves the cycle life and capacity of aqueous zinc-ion batteries even at high current densities. The above electrochemical test results fully demonstrate that the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure provided by this invention can significantly improve the cycle stability, rate performance, and reaction kinetics of aqueous zinc-ion batteries, showing promising application prospects. Furthermore, the electrode design strategy proposed in this invention can also be extended to other energy storage systems, providing new ideas for the design of high-performance battery electrode structures.

Claims

1. A method for preparing a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure, characterized in that, Includes the following steps: 1) Remove the oxide layer from the surface of copper, tin metal sheets and aluminum wire, and weigh copper, tin and aluminum metals respectively according to an atomic ratio of 15:15:70; 2) Place the weighed copper, tin and aluminum metals into a vacuum arc melting furnace protected by argon gas to melt and obtain a precursor alloy ingot with uniform alloy composition. 3) Cut the alloy ingot into metal sheets with a thickness of 400 μm using a diamond wire cutter, and remove the oxide layer on the surface of the metal sheets; 4) The metal sheet is placed in KOH solution and dealloyed at a preset temperature to prepare a Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure.

2. The method for preparing the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure according to claim 1, characterized in that: The alloy composition of the precursor alloy ingot mentioned in step 2) is Cu by atomic percentage. 15 Sn 15 Al 70 .

3. The method for preparing the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure according to claim 1, characterized in that: The KOH solution used in step 4) is a 6M KOH solution, the treatment temperature is 90℃, and the treatment time is 5 hours.

4. A Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure obtained by the preparation method according to any one of claims 1-3, characterized in that: The Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure has a hierarchical porous structure, consisting of macropore channels and mesopores distributed on the macropore ligaments. The macropore structure originates from the dealloying treatment of the Al phase in the precursor. The mesopores are formed by the selective dissolution of Al in the Al2Cu phase and are uniformly distributed on the surface of the macropore ligaments. The diameter of the macropores ranges from 100 to 400 nm, and the diameter of the mesopores ranges from 5 to 50 nm.

5. The application of the Cu3Sn / Cu6Sn5 composite electrode with a nanoporous structure according to claim 4, characterized in that: Using the composite electrode as the negative electrode of an aqueous zinc-ion battery, an aqueous zinc-ion battery is assembled.

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