Zinc-philic copper mesh interlayer for zinc battery and preparation method and application thereof

Abstract

The application discloses a zinc-phil copper mesh intermediate layer for zinc batteries and a preparation method and application thereof, and belongs to the field of biological materials and electrochemistry. The zinc-phil copper mesh intermediate layer for zinc batteries comprises a copper mesh and a bacterial cellulose layer deposited on the copper mesh, and the bacterial cellulose is deposited on the copper mesh through a gel electrophoresis method. The application constructs the bacterial cellulose with a suitable three-dimensional cross-linking network structure on the copper mesh through the gel electrophoresis method, provides a significant buffer layer for a zinc negative electrode, changes a traditional point-to-point contact mode into a large-area contact mode, forms a stable ion / electron three-dimensional transmission channel, and is helpful to improve the transmission efficiency of Zn 2+ and the structural stability of the zinc negative electrode. Meanwhile, the zinc-phil copper mesh intermediate layer with a porous three-dimensional structure serves as a carrier for zinc deposition, can promote the deposition and dissolution of zinc, is helpful to improve the reversibility of the zinc negative electrode, and further improves the cycle stability, rate performance and coulombic efficiency of the zinc metal negative electrode.

Description

Technical Field

[0001] This invention relates to the fields of biomaterials and electrochemical technology, specifically to a zinc-loving copper mesh interlayer for zinc batteries, its preparation method, and its application. Background Technology

[0002] With rapid economic and technological development, the shortage of traditional energy sources such as oil and natural gas is becoming increasingly prominent, and environmental pollution is becoming more and more serious. Therefore, developing clean energy, represented by energy storage batteries, has become a major goal. Although lithium-ion batteries have excellent energy storage performance and are one of the effective ways to solve the energy crisis and environmental problems, the development of lithium-ion batteries is limited by safety issues such as the flammability and poor thermal stability of organic electrolytes. Using aqueous electrolytes instead of organic electrolytes can effectively improve battery safety performance and reduce manufacturing costs. At the same time, the ionic conductivity of aqueous electrolytes is two orders of magnitude higher than that of organic electrolytes, which can enable batteries to have higher power density. Currently, aqueous batteries mainly include aqueous lithium-ion batteries, aqueous sodium-ion batteries, and aqueous zinc-ion batteries. Relatively speaking, zinc metal is low-cost, non-toxic, and has a low redox potential, making it more suitable for aqueous electrolytes and having greater research potential as the anode of zinc-ion batteries. Moreover, due to the high density of zinc and the two-electron reaction involved in the electrochemical reaction, zinc-ion batteries have higher volumetric energy density and huge application prospects, and are considered the preferred direction for the next generation of new power batteries and energy storage batteries.

[0003] Currently, the bottlenecks hindering the further development of zinc metal batteries mainly include poor interfacial contact, which easily leads to the formation of zinc dendrites. These rigid zinc dendrites can easily pierce the separator, causing internal short circuits. Furthermore, zinc dendrites increase the specific surface area of ​​the negative electrode, accelerating corrosion and hydrogen evolution rates, resulting in lower coulombic efficiency and excessively high interfacial activity between the electrode and electrolyte. During battery storage or operation, harmful side reactions occur, consuming charge and discharge capacity and reducing electrode reversibility. To address these issues, numerous scientists have conducted in-depth research, proposing strategies such as using protective coatings, modified separators, and electrolyte additives to guide zinc ion deposition behavior and thus suppress dendrite formation and corrosion. While these strategies can partially inhibit dendrite growth, they all have drawbacks, such as poor adhesion between the protective coating and the electrode, easy deformation of the coating, easy rupture of the modified separator, and high cost of electrolyte additives. Additionally, these strategies have low timeliness; dendrite formation is inevitable when the battery is cycled at high current densities for extended periods. For interfacial issues, methods such as constructing buffer layers are mainly used to alleviate poor interfacial contact and reduce interfacial impedance. In recent years, numerous studies have been reported on electrode / solid electrolyte interfaces modified with coatings, demonstrating excellent interface modification effects. However, the point-to-point contact between internal cathode particles remains a problem to be solved. Solid electrolytes cannot completely penetrate the gaps between particles, and the coating thickness of the solid electrolyte also affects electron transport in the system.

[0004] Therefore, it is of great significance to develop a zinc-loving copper mesh interlayer that can guide the uniform deposition of zinc ions while improving the zinc ion transport efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, one objective of this invention is to provide a zinc-loving copper mesh interlayer for zinc batteries, which can induce Zn... 2+ Uniform deposition can promote zinc deposition and dissolution, thereby increasing Zn content. 2+ This improves transmission efficiency and the structural stability of the zinc anode, thereby enhancing the cycle stability and rate performance of the zinc battery.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A zinc-loving copper mesh intermediate layer for zinc batteries includes a copper mesh and a bacterial cellulose layer deposited on the copper mesh, the bacterial cellulose being deposited on the copper mesh by gel electrophoresis.

[0008] This invention utilizes gel electrophoresis to deposit bacterial cellulose onto a copper grid, constructing a bacterial cellulose film with a three-dimensional cross-linked network structure on the copper grid. This results in a zinc-loving copper grid interlayer, which is then used in zinc batteries as a carrier for zinc deposition, inducing Zn deposition. 2+Uniform deposition on the copper mesh interlayer effectively suppresses the growth of zinc dendrites. Simultaneously, this zinc-loving copper mesh interlayer provides a significant buffer layer for the zinc anode, transforming the traditional point-to-point contact into a large-area contact, forming a stable three-dimensional ion / electron transport channel, which helps improve the zinc anode's performance. 2+ Transmission efficiency and structural stability. Furthermore, the three-dimensional porous zinc-loving copper mesh interlayer promotes zinc deposition and dissolution, contributing to improved battery reversibility. It also provides good electrolyte permeability, slowing electrode degradation and thus significantly improving battery stability and reversibility, enhancing the cycle stability of the zinc metal anode and the battery's rate performance, ultimately increasing battery efficiency and lifespan.

[0009] The zinc-loving copper mesh interlayer obtained by gel electrophoresis in this invention has the following two characteristics: ① It possesses stable structural strength and toughness. One-dimensional bacterial cellulose is deposited onto the copper mesh via gel electrophoresis to construct an ordered three-dimensional cross-linked network structure, with the one-dimensional bacterial cellulose serving as the Zn source. 2+ A continuous linear channel at the nanoscale, and an overall three-dimensional network structure formed by interconnected one-dimensional bacterial cellulose, are used for the continuous transport of Zn in the electrolyte. 2+ After the electrolyte solution successfully wets the three-dimensional network of the bacterial cellulose membrane, the traditional point-to-point contact is transformed into a large-area contact, forming a stable three-dimensional ion / electron transport channel, which helps to improve Zn concentration. 2+ Transport efficiency and structural stability of the zinc anode. ② Introducing negatively charged groups such as -COOH and -OH onto the copper mesh via bacterial cellulose facilitates Zn adsorption. 2+ This makes the local charge distribution more uniform and induces Zn 2+ Uniform deposition effectively inhibits the growth of zinc dendrites and slows down the degradation rate of the electrode.

[0010] In this invention, the thickness of the bacterial cellulose layer can be 0.01 to 0.10 mm, preferably 0.05 mm.

[0011] In this invention, the method for preparing the zinc-loving copper mesh interlayer for zinc batteries includes the following steps:

[0012] S1. Prepare a mixed hydrogel of bacterial cellulose and magnesium nitrate;

[0013] S2. The mixed hydrogel is deposited on a copper mesh by gel electrophoresis, dried, washed and dried again to obtain the zinc-loving copper mesh intermediate layer for zinc batteries.

[0014] Preferably, in step S1, the mass ratio of bacterial cellulose to magnesium nitrate in the mixed hydrogel is 10:(1-2).

[0015] Preferably, in step S2, the gel electrophoresis method uses a dual-electrode system consisting of a copper mesh and a platinum sheet, with a voltage of 3–20V and a time of 60–150s.

[0016] Preferably, the drying temperature is 60–80°C and the time is 12–24 hours.

[0017] Preferably, the specific washing procedure is as follows: place the copper mesh in anhydrous ethanol and ultrasonically wash it 3 to 5 times.

[0018] Another object of the present invention is to provide the application of the zinc-loving copper mesh interlayer as a zinc deposition carrier in a zinc battery, wherein the zinc-loving copper mesh interlayer is located between the negative electrode and the separator.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) This invention constructs bacterial cellulose with a suitable three-dimensional cross-linked network structure on a copper grid using gel electrophoresis, providing a significant buffer layer for the zinc anode. This transforms the traditional point-to-point contact method into a large-area contact, forming a stable ion / electron three-dimensional transport channel, which helps to improve the Zn anode. 2+ This improves the transmission efficiency and structural stability of the zinc anode. Simultaneously, the zinc-loving copper mesh interlayer with a porous three-dimensional structure serves as a carrier for zinc deposition, promoting zinc deposition and dissolution, thus enhancing the reversibility of the zinc anode and consequently improving its cycle stability, rate performance, and coulombic efficiency.

[0021] (2) The NH4VO3||Zn full cell using the copper mesh intermediate layer of this invention as the zinc deposition support, after 2500 stable cycles at a current density of 5 A / g, still maintains a specific capacity of 90 mAh / g, with a capacity retention of 78.26% and a coulombic efficiency of 98.4%, demonstrating good capacity retention and coulombic efficiency. The Zn||Zn symmetric cell using the copper mesh intermediate layer of this invention as the zinc deposition support, at a current density of 5 mA / g... -2 The current density, charge / discharge time are 12 minutes each, and the specific capacity is 1 mAh cm⁻¹. -2 It exhibits stable cycling for over 550 hours, demonstrating good cycle stability. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the manufacturing process of the zinc-loving copper mesh intermediate layer for zinc batteries according to the present invention;

[0023] Figure 2 A schematic diagram of a button cell assembly for Zn||Zn symmetric cells and NH4VO3||Zn full cells;

[0024] Figure 3SEM images of the pure copper mesh and the zinc-loving copper mesh intermediate layer of Example 2;

[0025] Figure 4 Long-cycle diagram of a Zn||Zn symmetric cell with a zinc-free deposition carrier, a pure copper mesh as the zinc deposition carrier, and a zinc-loving copper mesh intermediate layer as the zinc deposition carrier (Example 2).

[0026] Figure 5 The cycling performance of the NH4VO3||Zn full cell using the zinc-loving copper mesh interlayer of Example 2 as the zinc deposition support is shown in the figure.

[0027] Figure 6 The CV diagram shows the NH4VO3||Zn full cell with the zinc-loving copper mesh interlayer of Example 2 as the zinc deposition support. Detailed Implementation

[0028] The applicant will now provide a detailed description of the method of the present invention with reference to specific embodiments, in order to enable those skilled in the art to clearly understand the present invention. However, the following embodiments should not be construed in any way as limiting the scope of protection claimed in the present invention.

[0029] Example 1

[0030] like Figure 1 As shown, the preparation method of the zinc-loving copper mesh interlayer for zinc batteries in this embodiment includes the following steps:

[0031] S1. Add the bacterial cellulose dispersion to the electrophoresis tank, dilute it 10 times with deionized water, and make the bacterial cellulose mass fraction 10%. Stir for 30 min to obtain a uniform suspension. Then add Mg(NO3)2 to the suspension and stir for 2 h to obtain a highly uniform and translucent mixed hydrogel. The mass fraction of Mg(NO3)2 in the mixed hydrogel is 2%.

[0032] S2. Fix the copper mesh and form a dual-electrode system with the platinum sheet electrode. Place it in the mixed hydrogel of step S1, apply a voltage of 3V to the working electrode, and electrophore for 150s to obtain a copper mesh modified with bacterial cellulose.

[0033] S3. Spread the bacterial cellulose-modified copper mesh flat in a petri dish, ensuring it adheres tightly to the surface. After standing for 1 minute, quickly transfer it to an electric heating drying oven for normal pressure drying at 80℃ for 15 hours. Then, ultrasonically wash it 3-5 times in 99% anhydrous ethanol for 1 minute each time. Finally, dry it in a 60℃ oven to obtain the zinc-loving copper mesh intermediate layer for zinc batteries (denoted as BC copper mesh). The thickness of the bacterial cellulose layer is 0.05 mm.

[0034] Example 2

[0035] The method for preparing the zinc-loving copper mesh interlayer for zinc batteries in this embodiment includes the following steps:

[0036] S1. Add the bacterial cellulose dispersion to the electrophoresis tank, dilute it 10 times with deionized water, and make the bacterial cellulose mass fraction 10%. Stir for 30 min to obtain a uniform suspension. Then add Mg(NO3)2 to the suspension and stir for 2 h to obtain a highly uniform and translucent mixed hydrogel. The mass fraction of Mg(NO3)2 in the mixed hydrogel is 2%.

[0037] S2. Fix the copper mesh and form a dual-electrode system with the platinum sheet electrode. Place it in the mixed hydrogel of step S1, apply a voltage of 5V to the working electrode, and electrophore for 120s to obtain a copper mesh modified with bacterial cellulose.

[0038] S3. Spread the bacterial cellulose-modified copper mesh flat in a petri dish, ensuring it adheres tightly to the surface. After standing for 1 minute, quickly transfer it to an electric heating drying oven for normal pressure drying at 80℃ for 15 hours. Then, ultrasonically wash it 3-5 times in 99% anhydrous ethanol for 1 minute each time. Finally, dry it in a 60℃ oven to obtain the zinc-loving copper mesh intermediate layer for zinc batteries (denoted as BC copper mesh). The thickness of the bacterial cellulose layer is 0.05 mm.

[0039] Figure 3 The images show SEM images of pure copper mesh and BC copper mesh. As can be seen from the images, bacterial cellulose is uniformly deposited on the copper mesh, and one-dimensional bacterial cellulose is deposited along the three-dimensional cross-linked network of the copper mesh, interconnecting to form an overall three-dimensional network structure.

[0040] Example 3

[0041] The method for preparing the zinc-loving copper mesh interlayer for zinc batteries in this embodiment includes the following steps:

[0042] S1. Add the bacterial cellulose dispersion to the electrophoresis tank, dilute it 10 times with deionized water, and make the bacterial cellulose mass fraction 10%. Stir for 30 min to obtain a uniform suspension. Then add Mg(NO3)2 to the suspension and stir for 2 h to obtain a highly uniform and translucent mixed hydrogel. The mass fraction of Mg(NO3)2 in the mixed hydrogel is 1%.

[0043] S2. Fix the copper mesh and form a dual-electrode system with the platinum sheet electrode. Place it in the mixed hydrogel of step S1, apply a voltage of 10V to the working electrode, and electrophore for 90s to obtain a copper mesh modified with bacterial cellulose.

[0044] S3. Spread the bacterial cellulose-modified copper mesh flat in a petri dish, ensuring it adheres tightly to the surface. After standing for 1 minute, quickly transfer it to an electric heating drying oven for normal pressure drying at 70℃ for 20 hours. Then, ultrasonically wash it 3-5 times in 99% anhydrous ethanol for 1 minute each time. Finally, dry it in a 60℃ oven to obtain the zinc-loving copper mesh intermediate layer for zinc batteries (denoted as BC copper mesh), with a bacterial cellulose layer thickness of 0.05 mm.

[0045] Example 4

[0046] The method for preparing the zinc-loving copper mesh interlayer for zinc batteries in this embodiment includes the following steps:

[0047] S1. Add the bacterial cellulose dispersion to the electrophoresis tank, dilute it 10 times with deionized water, and make the bacterial cellulose mass fraction 10%. Stir for 30 min to obtain a uniform suspension. Then add Mg(NO3)2 to the suspension and stir for 2 h to obtain a highly uniform and translucent mixed hydrogel. The mass fraction of Mg(NO3)2 in the mixed hydrogel is 2%.

[0048] S2. Fix the copper mesh and form a dual-electrode system with the platinum sheet electrode. Place it in the mixed hydrogel of step S1, apply a voltage of 20V to the working electrode, and electrophore for 60s to obtain a copper mesh modified with bacterial cellulose.

[0049] S3. Spread the bacterial cellulose-modified copper mesh in a petri dish, ensuring it adheres tightly to the surface. After standing for 1 minute, quickly transfer it to an electric heating drying oven for normal pressure drying at 60℃ for 24 hours. Then, ultrasonically wash it 3-5 times in 99% anhydrous ethanol for 1 minute each time. Finally, dry it in a 60℃ oven to obtain the zinc-loving copper mesh intermediate layer for zinc batteries. The thickness of the bacterial cellulose layer is 0.05 mm.

[0050] Application examples

[0051] Button cells of Zn||Zn symmetric cells and NH4VO3||Zn full cells were prepared using the zinc-loving copper mesh intermediate layer of Examples 1-4 as zinc deposition carriers, and their electrochemical performance was tested.

[0052] The assembly flowchart of the Zn||Zn symmetric cell is as follows: Figure 2 As shown in the left figure, a glass fiber membrane is used as the diaphragm, and a 2M ZnSO4 aqueous solution is used as the electrolyte, according to... Figure 2 As shown in the left figure, the negative electrode shell, zinc sheet, zinc-loving copper mesh intermediate layer (BC copper mesh), separator, zinc-loving copper mesh intermediate layer (BC copper mesh), zinc sheet, gasket, spring sheet and positive electrode shell are stacked in sequence to assemble a button cell.

[0053] The assembly flowchart of the NH4VO3||Zn full cell is as follows: Figure 2 As shown in the right figure, the preparation method of the positive electrode is as follows: (NH4)2V 10 O 25 • 8H₂O nanosheets were mixed with PVDF and Super P at a mass ratio of 7:2:1, NMP solvent was added, and the mixture was stirred until homogeneous. The mixture was then coated onto carbon paper and dried in a vacuum oven at 80°C for 24 hours. After cooling, it was cut into circular films with a diameter of 12 mm to obtain the positive electrode. Then, using a zinc sheet as the negative electrode, glass fiber as the separator, and 2M zinc trifluoromethanesulfonate as the electrolyte, the mixture was processed according to… Figure 2 The sequence shown in the right figure is used to assemble an NH4VO3||Zn button cell.

[0054] The assembled batteries were tested for electrochemical performance using a battery testing system.

[0055] Figure 4 The figure shows the long-cycle diagrams of a Zn||Zn symmetric cell with no zinc deposition support, a pure copper mesh as the zinc deposition support, and a zinc-loving copper mesh interlayer as the zinc deposition support (Example 2). As can be seen from the figure, the Zn||Zn symmetric cell with the zinc-loving copper mesh interlayer as the zinc deposition support achieves a long-cycle performance of 5 mA cm⁻¹. -2 At a current density of 1 mAh cm⁻¹ -2 At specific capacity, it exhibits stable cycling for over 550 hours. The combination of copper mesh and BC insulation network results in a more uniform charge distribution, and the growth of one-dimensional bacterial cellulose along the three-dimensional cross-linked network of the copper mesh provides Zn. 2+ Provides ordered migration channels for nanopolymer chains, ensuring Zn 2+ High-speed transmission. Modifications to the BC network can transmit Zn... 2+ It is adsorbed onto the intermediate layer of the copper mesh and optimizes the Zn content in the aqueous electrolyte. 2+ The concentration distribution of the copper mesh induces uniform Zn deposition, reduces the interfacial impedance of the zinc anode, and decreases the corrosion reaction of zinc, thereby slowing down the degradation rate of the electrode. The combination of copper mesh and BC insulation network effectively reduces the zinc nucleation resistance and local current density, thus minimizing the zinc nucleation overpotential, obtaining a small initial zinc nucleus size, and suppressing the formation of zinc dendrites. Furthermore, the introduction of the copper mesh and BC insulation network can effectively modify Zn. 2+ Active center, optimizing the active center and Zn 2+ The interaction between them lowers the diffusion barrier and ensures the Zn 2+The deposition and dissolution of zinc are facilitated. Therefore, compared to zinc-free deposition supports and pure copper mesh as the zinc deposition support, the combination of copper mesh and BC network as the zinc deposition support has unique advantages. Local cycling diagrams also show that, compared to bare zinc Zn||Zn symmetric cells without a zinc deposition support and Zn||Zn symmetric cells with pure copper mesh as the zinc deposition support, the Zn||Zn symmetric cell with the zinc-loving copper mesh interlayer of Example 2 as the zinc deposition support exhibits more stable voltage polarization and maintains a stable overpotential of 42mV, demonstrating stable long-cycle performance. This indicates that the zinc-loving copper mesh interlayer can promote the dissolution of Zn. 2+ Uniform deposition inhibits the growth of zinc dendrites, resulting in a significant improvement in cycle stability.

[0056] Figure 5 The figure shows the cycling performance of the NH4VO3||Zn full cell using the zinc-loving copper mesh interlayer of Example 2 as the zinc deposition support. As can be seen from the figure, the NH4VO3||Zn full cell using the zinc-loving copper mesh interlayer as the zinc deposition support maintains a specific capacity of 90 mAh / g after 2500 stable cycles at a current density of 5 A / g, with a capacity retention of 78.26% and a coulombic efficiency of 98.4%, exhibiting good capacity retention and coulombic efficiency. The voltage-capacity curve also shows that during the initial cycling process, the capacity increases with the activation of the battery interior and the insertion of active materials. At 2000 cycles, the fully charged specific capacity still reaches 98 mAh / g, demonstrating excellent long-cycle performance and superior long-cycle capacity.

[0057] Figure 6 The figure shows the CV curve of the NH4VO3||Zn full cell using the zinc-loving copper mesh interlayer of Example 2 as the zinc deposition support. It can be seen from the figure that the potentials of the two oxidation peaks are approximately 0.6V and 1.0V, corresponding to VO3. - In the two oxidation processes, the potentials of the two reduction peaks are approximately 0.6V and 1.0V, with roughly the same peak spacing. Furthermore, the ratio of the oxidation peak current to the reduction peak current is close to 1, indicating that the reaction has good reversibility. At this point, VO3... - The oxides were reduced to VO3. - .

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. The application of a zinc-loving copper mesh interlayer in zinc batteries, characterized in that, The zinc-loving copper mesh intermediate layer is located between the negative electrode and the separator; the zinc-loving copper mesh intermediate layer includes a copper mesh and a bacterial cellulose layer deposited on the copper mesh, the bacterial cellulose being deposited on the copper mesh by gel electrophoresis.

2. The application according to claim 1, characterized in that, The thickness of the bacterial cellulose layer is 0.01~0.10 mm.

3. The application according to claim 1, characterized in that, The thickness of the bacterial cellulose layer is 0.05 mm.

4. The application according to claim 1, characterized in that, The method for preparing the zinc-loving copper mesh interlayer includes the following steps: S1. Prepare a mixed hydrogel of bacterial cellulose and magnesium nitrate; S2. The mixed hydrogel is deposited on a copper mesh by gel electrophoresis, dried, washed and dried again to obtain the zinc-loving copper mesh intermediate layer for zinc batteries.

5. The application according to claim 4, characterized in that, In step S1, the mass ratio of bacterial cellulose to magnesium nitrate in the mixed hydrogel is 10:(1~2).

6. The application according to claim 4, characterized in that, In step S2, the gel electrophoresis method uses a copper mesh and a platinum sheet to form a dual-electrode system, with a voltage of 3~20V and a time of 60~150s.

7. The application according to claim 4, characterized in that, The drying process is carried out at a temperature of 60-80℃ for 12-24 hours.

8. The application according to claim 4, characterized in that, The specific washing procedure is as follows: Place the copper mesh in anhydrous ethanol and ultrasonically wash it 3-5 times.

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