Preparation method of indium-based coating composite diaphragm for aqueous zinc ion battery

Abstract

The invention discloses a preparation method of an indium-based coating composite diaphragm for an aqueous zinc ion battery. The indium-based oxide target material is sputtered to the surface of the glass fiber diaphragm by adopting direct-current magnetron sputtering equipment, and different aqueous zinc ion battery indium-based coating composite diaphragms are obtained by regulating and controlling sputtering power, sputtering time and sputtering pressure. The indium-based coating composite diaphragm is used as a diaphragm of a water-based zinc ion battery, shows good reversibility, and shows stable long cycle performance under the current density of 2Ag <-1 >. The preparation method comprises the following steps: putting a glass fiber diaphragm and an indium-based oxide target material into corresponding positions of magnetron sputtering equipment, setting sputtering process parameters, slicing a material obtained after sputtering, and taking the sliced material as the diaphragm of the aqueous zinc ion battery. The preparation method has the characteristics of simple preparation process, good repeatability and excellent electrochemical performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of zinc-ion batteries and relates to a preparation method of an indium-based coated composite separator for aqueous zinc-ion batteries. Background Art

[0002] In the design of key components of aqueous zinc-ion batteries ( Aqueous Zinc-Ion Batteries , AZIBs), as the core functional layer for isolating the positive and negative electrodes and regulating ion transport, the material structure and interfacial properties of the separator play a decisive role in the plating / stripping behavior of the zinc electrode and the long-term cycling stability of the battery.

[0003] As an important part of the battery, the separator plays a crucial role in regulating the zinc plating / stripping behavior and maintaining the battery performance. From the perspective of electrochemical kinetics, the microscopic pore structure, surface chemical properties, and ion conduction characteristics of the separator jointly affect the zinc ion concentration gradient distribution at the zinc negative electrode interface, and then regulate the deposition morphology of zinc metal through the mass transfer process. When the separator has precise ion sieving ability and directional transport channels, it can effectively inhibit concentration polarization, guide the uniform nucleation and deposition of zinc ions on the electrode surface, and thus construct a stable interface; therefore, the strategy for separator design will be beneficial to the stability of the zinc negative electrode. However, the currently widely used glass fiber separator exposes significant defects under high-rate charge and discharge conditions: although its three-dimensional disordered fiber packing structure can provide physical isolation function, the ion conduction path shows a high degree of randomness, resulting in serious transport resistance during the migration of zinc ions, specifically manifested as: ① at a higher current density, the ionic conductivity inside the separator drops suddenly to a lower level, significantly lower than the intrinsic conductivity of the aqueous electrolyte, leading to serious interfacial polarization; ② the disordered pore structure causes the lack of a directional driving force for zinc ions during migration, forming local concentration hotspots on the electrode surface and inducing the preferential growth of zinc dendrites. This non-uniform deposition behavior not only accelerates the loss of active substances, but may also penetrate the separator and cause internal short circuit, becoming the key bottleneck restricting the practical application of AZIBs.

[0004] The separator should be able to conduct ions well and, while ensuring that the positive and negative electrodes do not short-circuit, also allow zinc ions to pass through easily. However, the migration of ions in the glass fiber separator is disordered, which leads to the randomness of zinc ions both inside the separator and during the migration towards the zinc negative electrode, which may result in non-uniform zinc plating and thus cause the failure of aqueous zinc-ion batteries (AZIBs).

[0005] It is worth noting that most of the reported new separators for aqueous zinc-ion batteries only achieve physical separation of the positive and negative electrodes, but have poor in-plane conductivity and zincophilicity. The lack of in-plane conductive and zincophilic active sites leads to two core problems: First, the lack of a continuous conductive path results in significant unevenness in the electric field distribution within the membrane plane, exacerbating the spatial difference in zinc-ion migration. Second, the inert surface chemical properties cannot provide effective nucleation sites, resulting in a too high nucleation overpotential for zinc deposition. The above defects jointly lead to the attenuation of Coulomb efficiency and the deterioration of capacity retention rate during the cycling of the battery. Therefore, it is necessary to develop high-quality separators to ensure the cycling stability and service life of zinc-ion batteries. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method for an indium-based coating composite separator for aqueous zinc-ion batteries, which has a simple process, and the separator has a very high ion migration rate and strong in-plane electronic conductivity, solving the problems of poor cycling stability and short service life of aqueous zinc-ion batteries.

[0007] The technical solution of the present invention is realized as follows: A preparation method for an indium-based coating composite separator for aqueous zinc-ion batteries, wherein the indium-based coating composite separator is composed of an indium-based oxide coating and a glass fiber separator matrix; the preparation method is a direct current magnetron sputtering method, including the following steps: (1) Clean the glass fiber separator with a UV light cleaning machine, and place the glass fiber separator into the magnetron sputtering cavity. (2) Place the indium-based oxide target into the magnetron sputtering cavity for pre-sputtering.

[0008] (3) Adjust the sputtering pressure in the vacuum chamber to 1~10×10 -4 Pa; (4) Adjust the power parameters of the magnetron sputtering equipment to 150~250 W / cm 2 , the sputtering time to 1~15 min, and the sputtering pressure to 0.2~1.0 Pa; (5) Operate the equipment to sputter indium-based oxide on the glass fiber separator to obtain an indium-based zinc-ion battery separator. Further, the glass fiber separator described in step (1) is GF / D.

[0009] Further, in step (1), the glass fiber separator is cleaned with a UV light cleaning machine for 10~15 min.

[0010] Further, the pre-sputtering time described in step (2) is 0.5~3 min, and the pre-sputtering power density is 150~250 W / cm 2 .

[0011] Further, the indium-based oxide target in step (2) is a commercial indium zinc oxide (IZO) target or a commercial indium tin oxide (ITO) target, with a purity > 99.9%.

[0012] Further, the power parameter in step (4) is 150 W; the optimal sputtering time is 10 min; the sputtering pressure is preferably 0.4 Pa.

[0013] Further, during the sputtering process in step (4), argon with a purity > 95% is introduced, and the flow rate is controlled to be 50 - 60 sccm after the introduction of argon.

[0014] Further, the sputtering mass of the indium-based coated composite separator for zinc ion batteries is 0.08 - 1.22 mg.

[0015] Further, the indium-based coated composite separator for aqueous zinc ion batteries is prepared by the above preparation method.

[0016] Further, the composite separator is applicable to aqueous zinc ion batteries.

[0017] Further, the application of the aqueous zinc ion battery in deep-sea energy storage batteries.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a preparation method for an indium-based coated composite separator for aqueous zinc ion batteries. Utilizing the characteristics of strong zinc affinity and good conductivity of indium-based oxides, its zinc affinity stems from a specific surface chemical structure and electron state distribution, which can form a strong interaction with zinc ions, provide abundant and uniform deposition sites for the electroplating process of zinc ions, effectively reduce the nucleation overpotential of zinc ions on the electrode surface, and promote the uniform adsorption and deposition of zinc ions on the electrode surface, fundamentally improving the deposition behavior of zinc ions.

[0019] In addition, the good zinc affinity of indium-based oxides provides more abundant deposition sites for the electroplating of zinc ions, which is beneficial to the electroplating of zinc ions. The coating formed on the separator substrate material constructs an efficient in-plane conductive network, which can evenly distribute the in-plane electric field, guide the zinc ions to receive a more uniform electric field driving force during migration, and thus achieve the uniform deposition of zinc ions on the electrode surface, significantly reducing the formation and growth of dendrites. And the uniform deposition of zinc ions can effectively inhibit the excessive growth of dendrites, avoid the internal short circuit problem of the battery caused by dendrites piercing the separator, and greatly improve the cycle stability of the battery. It has been experimentally verified that the aqueous zinc ion battery using the composite separator prepared by the present invention can maintain a stable capacity output during long-term cycling, and exhibits a capacity retention rate of more than 86.58% after 5000 cycles at a current density of 2Ag -1 and has a significantly extended cycle life compared with traditional separators.

[0020] Therefore, it is introduced onto the separator substrate material, which is suitable for separating the positive electrode and the negative electrode. The provided good in-plane conductivity is conducive to guiding the uniform in-plane electric field for zinc ion deposition, making the zinc ion deposition uniform, significantly reducing the growth of dendrites, and improving the cycle stability of the zinc ion battery; it greatly improves the cycle stability and rate performance during the operation of the zinc ion battery.

[0021] In terms of the preparation process, the present invention has prominent advantages. The entire production process is simple and efficient. By reasonably designing the combination mode of the coating material and the substrate material and adopting a mature and easy-to-control preparation process, uniform coating of the indium-based coating on the separator substrate can be achieved. This method does not require complex equipment and harsh reaction conditions, has good repeatability and production adaptability, and provides a solid technical foundation for large-scale industrial production. Brief Description of the Drawings

[0022] Figure 1 The indium-based coating composite separator is prepared by using the preparation method of an indium-based coating composite separator for aqueous zinc ion batteries provided by the present invention. Among them, the left figure is the ITO coating composite separator, Figure 1 and the right figure is the IZO coating composite separator.

[0023] Figure 2 This is a scanning electron microscope image of an indium-based coating composite separator for aqueous zinc ion batteries provided by the present invention. Among them, the left figure is the ITO coating composite separator, Figure 1 and the right figure is the IZO coating composite separator.

[0024] Figure 3 This is the long-term cycling performance graph of an aqueous zinc ion battery at a current density of 2Ag -1 Among them, the left figure is the aqueous zinc ion battery prepared with the ITO coating composite separator, and the right figure is the aqueous zinc ion battery prepared with the IZO coating composite separator. Detailed Description of the Invention

[0025] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0026] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0027] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can all be obtained from commercial channels.

[0028] Example 1: Place a circular glass fiber diaphragm with a diameter of 125 mm and an ITO target with a diameter of 76 mm in the corresponding positions in the existing magnetron sputtering equipment chamber respectively. Then adjust the air pressure of the magnetron sputtering equipment to 0.4 Pa, adjust the sputtering power to 150 W, and start sputtering. During the sputtering process, introduce argon with a purity > 95%, and control the flow rate to 50 sccm after introducing argon. When the sputtering time reaches 10 min, stop the equipment. The sputtering mass is 1 mg, and a glass fiber diaphragm with an ITO coating is obtained. Example 2: Place a circular glass fiber diaphragm with a diameter of 125 mm and an IZO target with a diameter of 76 mm in the corresponding positions in the existing magnetron sputtering equipment chamber respectively. Then adjust the air pressure of the magnetron sputtering equipment to 0.4 Pa, adjust the sputtering power to 150 W, and start sputtering. During the sputtering process, introduce argon with a purity > 95%, and control the flow rate to 50 sccm after introducing argon. When the sputtering time reaches 10 min, stop the equipment. The sputtering mass is 1 mg, and a glass fiber diaphragm with an IZO coating is obtained.

[0029] Figures 1-3 Result analysis: IZO or ITO is evenly distributed on the surface of the indium-based coating composite diaphragm obtained by magnetron sputtering, effectively solving the technical problems of agglomeration and uneven distribution of traditional diaphragm coatings. The precise control of the thin film growth process by the magnetron sputtering method realizes the atomic-level epitaxial growth of indium-based oxides on the surface of the glass fiber substrate, forming a defect-free continuous conductive film. Figure 2 It can be seen that ITO / IZO is wrapped around single glass fibers, different from traditional covering coatings, ensuring good electrolyte wettability.

[0030] At the same time, in the full cell test results, the prepared GF@ITO and GF@IZO composite diaphragms show excellent cycle stability: The GF@ITO diaphragm shows a capacity retention rate of 90.20% after 5000 cycles at a current density of 2 Ag -1 The GF@IZO diaphragm shows a capacity retention rate of 86.58% after 5000 cycles at a current density of 2 Ag -1 The performance far exceeds that of the GF diaphragm. This performance breakthrough stems from the dual advantages of the uniform coating construction: Interface regulation mechanism: The evenly distributed IZO / ITO coating provides a high density of zincophilic active sites, significantly reducing the nucleation overpotential of zinc ions on the electrode surface and promoting uniform zinc deposition / stripping behavior.

[0031] Conductive network optimization: A continuous indium-based oxide coating forms an in-plane conductive network inside the separator. Finite element simulation confirms that this network can effectively reduce the unevenness of the electric field distribution in the plane of the separator, inhibit the local current concentration phenomenon under high current density, and thus avoid the directional growth of zinc dendrites.

[0032] Compared with traditional glass fiber separators, the composite separator prepared in this invention exhibits a lower Coulombic efficiency decay during long cycles. In addition, due to the unique electron conduction characteristics of the indium-based coating, the ionic conductivity of the composite separator is significantly improved compared with traditional separators, effectively reducing the internal resistance of the battery. At the same time, the zincophilic coating significantly inhibits dendrite growth by optimizing the zinc ion deposition behavior, achieving a more uniform zinc negative electrode interface. The above performances verify the key role of the uniform indium-based coating in enhancing conductivity and optimizing zinc deposition behavior.

Claims

1. A preparation method of an indium-based coating composite separator for aqueous zinc-ion batteries, characterized in that, The indium-based coating composite separator for aqueous zinc-ion batteries is obtained by sputtering an indium-based oxide target onto a substrate glass fiber separator in a vacuum chamber using a DC magnetron sputtering method, including the following steps: (1) Clean the glass fiber separator using a UV light cleaning machine and place the glass fiber separator into the magnetron sputtering chamber; (2) Place the indium-based oxide target into the magnetron sputtering chamber for pre-sputtering; (3) The sputtering pressure in the vacuum chamber is adjusted to 1~10×10 -4 Pa; (4) Adjust the power parameter of the magnetron sputtering equipment to 150 - 250 W / cm 2 , the sputtering time to 1 - 15 min, and the sputtering pressure to 0.2 - 1.0 Pa; (5) Operate the equipment to sputter indium-based oxide onto the glass fiber separator to obtain the indium-based zinc-ion battery separator.

2. The preparation method of the indium-based coating composite separator for the aqueous zinc-ion battery according to claim 1, wherein The glass fiber separator described in step (1) is GF / D.

3. The preparation method of the indium-based coating composite separator for the aqueous zinc-ion battery according to claim 1, characterized in that, In step (1), the glass fiber separator is cleaned using a UV light cleaning machine for 10 - 15 min.

4. The preparation method of the indium-based coating composite separator for the aqueous zinc-ion battery according to claim 1, wherein, The pre-sputtering time described in step (2) is 0.5 to 3 minutes, and the pre-sputtering power density is 150 to 250 W / cm 2 .

5. The preparation method of the indium-based coating composite separator for the aqueous zinc ion battery according to claim 1, characterized in that, The indium-based oxide target described in step (2) is an indium zinc oxide target or an indium tin oxide target.

6. The preparation method of the indium-based coating composite separator for the aqueous zinc-ion battery according to claim 1, wherein During the sputtering process described in step (4), argon with a purity > 95% is introduced, and after introducing argon, the flow rate is controlled to be 50 - 60 sccm.

7. The preparation method of the indium-based coated composite separator for the aqueous zinc-ion battery according to claim 1, wherein The sputtering mass of the indium-based coating composite separator for zinc-ion batteries is 0.08 - 1.22 mg.

8. An indium-based coated composite separator for an aqueous zinc-ion battery, characterized in that, It is obtained by using the preparation method of the indium-based coating composite separator for aqueous zinc-ion batteries according to any one of claims 1 - 7.

9. The indium-based coating composite separator according to claim 8, wherein the composite separator is applicable to aqueous zinc-ion batteries.

10. The indium-based coating composite separator according to claim 9, wherein the application of the aqueous zinc-ion battery in deep-sea energy storage batteries.

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