Aqueous zinc ion battery indium-based coating composite diaphragm and preparation method thereof

Abstract

The present invention discloses a method for preparing an indium-based coating composite diaphragm for aqueous zinc-ion batteries. A DC magnetron sputtering device is used to sputter an indium-based oxide target onto the surface of a glass fiber diaphragm. Different indium-based coating composite diaphragms for aqueous zinc-ion batteries are obtained by regulating the sputtering power, sputtering time, and sputtering pressure. The indium-based coating composite diaphragm exhibits good reversibility as a diaphragm for aqueous zinc-ion batteries. ‑1 The invention exhibits stable long-cycle performance at low current densities. The preparation steps include placing a glass fiber separator and an indium-based oxide target in corresponding positions in a magnetron sputtering apparatus, setting sputtering process parameters, and slicing the resulting sputtered material for use as a separator for aqueous zinc-ion batteries. The invention features a simple preparation process, good reproducibility, and excellent electrochemical performance.

Description

Technical Field

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

[0002] In aqueous zinc-ion batteries ( Aqueous Zinc-Ion Batteries In the key component design of Zn-based IGBs (AZIBs), the separator serves as the core functional layer that isolates the positive and negative electrodes and regulates ion transport. Its material structure and interface properties play a decisive role in the electroplating / stripping behavior of the zinc electrode and the long-term cycle stability of the battery.

[0003] As an important component of the battery, the separator plays a vital role in regulating zinc plating / stripping behavior and maintaining battery performance. From the perspective of electrochemical kinetics, the separator's microscopic pore structure, surface chemical properties, and ion conductivity characteristics jointly affect the zinc ion concentration gradient distribution at the zinc negative electrode interface, thereby regulating the deposition morphology of zinc metal through the mass transfer process. When the separator has precise ion screening capabilities and directional transmission channels, it can effectively suppress concentration polarization and guide zinc ions to uniformly nucleate and deposit on the electrode surface, thereby constructing a stable interface; therefore, strategies for separator design will be beneficial to the stability of the zinc negative electrode. However, the widely used glass fiber separators currently exhibit significant drawbacks under high-rate charge and discharge conditions: while their three-dimensional, disordered fiber stacking structure provides physical isolation, the ion conduction pathways are highly random, leading to severe transport resistance during zinc ion migration. Specifically, at high current densities, the ionic conductivity within the separator plummets to a low level, significantly lower than the intrinsic conductivity of the aqueous electrolyte, causing severe interfacial polarization. Furthermore, the disordered pore structure results in a lack of directional driving force for zinc ion migration, forming localized 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 material but also potentially penetrates the separator, causing internal short circuits, becoming a key bottleneck restricting the practical application of AZIBs.

[0004] The separator should be able to conduct ions well and allow zinc ions to pass easily without short-circuiting the positive and negative electrodes. However, the migration of ions within the glass fiber separator is disordered, resulting in random migration of zinc ions both within the separator and to the zinc anode. This can lead to uneven zinc plating and thus failure of aqueous zinc-ion batteries (AZIBs).

[0005] It is worth noting that most of the new separators for aqueous zinc-ion batteries reported so far only achieve physical separation of the positive and negative electrodes, while having poor in-plane conductivity and zinc affinity. The lack of in-plane conductivity and zinc-affinity active sites leads to two core problems: first, the lack of a continuous conductive path makes the electric field distribution in the membrane plane significantly uneven, exacerbating the spatial differences in zinc ion migration; second, the inert surface chemical properties cannot provide effective nucleation sites, resulting in excessively high nucleation overpotential for zinc deposition. The above defects together lead to coulombic efficiency decay and capacity retention degradation during battery cycling. Therefore, it is necessary to develop high-quality separators to ensure the cycle stability and service life of zinc-ion batteries. Summary of the Invention

[0006] The purpose of the present invention is to provide an indium-based coated composite diaphragm for an aqueous zinc ion battery and a preparation method thereof. The process is simple, and the diaphragm has high ion mobility and strong in-plane electronic conductivity, thereby solving the problems of poor cycle stability and short life of aqueous zinc ion batteries.

[0007] The technical solution of the present invention is achieved as follows: an indium-based coating composite diaphragm for an aqueous zinc ion battery, wherein the indium-based coating composite diaphragm is composed of an indium-based oxide coating and a glass fiber diaphragm substrate; the preparation method is a DC magnetron sputtering method, comprising the following steps:

[0008] (1) Use a UV light cleaning machine to clean the glass fiber diaphragm for 10-15 minutes, and then place the glass fiber diaphragm into the magnetron sputtering chamber;

[0009] (2) Place the indium-based oxide target into the magnetron sputtering chamber for pre-sputtering. The pre-sputtering time is 0.5~3min and the pre-sputtering power density is 150~250W / cm 2 ;

[0010] (3) The sputtering pressure in the vacuum chamber is adjusted to 1~10×10 -4 Pa;

[0011] (4) Adjust the power parameters of the magnetron sputtering equipment to 150~250W / cm 2 , sputtering time is 1~15min and sputtering pressure is 0.2~1.0Pa;

[0012] (5) operating the equipment to sputter indium-based oxide on the glass fiber separator to produce an indium-based zinc ion battery separator;

[0013] Furthermore, the glass fiber separator in step (1) is GF / D;

[0014] Furthermore, the indium-based oxide target material in step (2) is a commercial indium zinc oxide (IZO) target material or a commercial indium tin oxide (ITO) target material;

[0015] Furthermore, the power parameter in step (4) is 150W; the optimal sputtering time is 10 minutes; and the sputtering pressure is preferably 0.4 Pa.

[0016] Furthermore, during the sputtering process in step (4), argon gas with a purity of >95% is introduced, and the flow rate is controlled to be 50-60 sccm after the argon gas is introduced.

[0017] Furthermore, the sputtering mass of the indium-based coating composite diaphragm of the zinc ion battery is 0.08~1.22mg.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a method for preparing an indium-based coated composite diaphragm that can be used for aqueous zinc-ion batteries. The method utilizes the strong zinc affinity and good electrical conductivity of indium-based oxide. Its zinc affinity is derived from its specific surface chemical structure and electronic state distribution. It can form a strong interaction with zinc ions, provide abundant and uniform deposition sites for the zinc ion electroplating process, effectively reduce the nucleation overpotential of zinc ions on the electrode surface, promote the uniform adsorption and deposition of zinc ions on the electrode surface, and fundamentally improve the deposition behavior of zinc ions.

[0020] In addition, the good zinc affinity of indium-based oxide 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 diaphragm base material constructs an efficient in-plane conductive network, which can evenly distribute the in-plane electric field and guide the zinc ions to be subjected to a more uniform electric field driving force during the migration process, thereby achieving uniform deposition of zinc ions on the electrode surface and greatly reducing the formation and growth of dendrites. The uniform zinc ion deposition can effectively inhibit the excessive growth of dendrites, avoid the problem of internal short circuit of the battery caused by dendrites piercing the diaphragm, and greatly improve the cycle stability of the battery. It has been verified experimentally that the aqueous zinc ion battery using the composite diaphragm prepared by the present invention can maintain a stable capacity output during long-term cycling. At 2Ag -1 At a current density of 1.5477 W / m, it exhibits a capacity retention rate of more than 86.58% after 5,000 cycles, and its cycle life is significantly extended compared to traditional diaphragms.

[0021] Therefore, it is introduced into the diaphragm base material, which is suitable for separating the positive and negative electrodes. The good in-plane conductivity provided is conducive to the uniform in-plane electric field to guide the zinc ion deposition, making the zinc ion deposition uniform, greatly reducing the growth of dendrites, and improving the cycle stability of the zinc ion battery; greatly improving the cycle stability and rate performance of the zinc ion battery during operation.

[0022] The present invention offers significant advantages in terms of preparation technology. The entire production process is simple and efficient. By rationally designing the combination of the coating material and the substrate material and employing a mature and easily controllable preparation process, uniform application of the indium-based coating on the diaphragm substrate is achieved. This method does not require complex equipment or demanding reaction conditions, exhibits excellent repeatability and production adaptability, and provides a solid technical foundation for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The indium-based coating composite diaphragm is prepared by using the preparation method of the indium-based coating composite diaphragm for aqueous zinc ion batteries provided by the present invention, wherein the left figure is an ITO coating composite diaphragm, Figure 1 The right picture is an IZO-coated composite diaphragm.

[0024] Figure 2 This is a scanning electron microscope image of an indium-based coating composite diaphragm that can be used for aqueous zinc-ion batteries provided by the present invention. The left image is an ITO-coated composite diaphragm. Figure 1 The right picture is an IZO-coated composite diaphragm.

[0025] Figure 3 For aqueous zinc ion batteries at 2Ag -1 Long cycle performance diagram under current density, where the left picture is an aqueous zinc-ion battery prepared with an ITO-coated composite diaphragm, and the right picture is an aqueous zinc-ion battery prepared with an IZO-coated composite diaphragm. DETAILED DESCRIPTION

[0026] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0027] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0028] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0029] Example 1:

[0030] A circular glass fiber diaphragm with a diameter of 125 mm and an ITO target with a diameter of 76 mm were placed in the corresponding positions of the existing magnetron sputtering equipment chamber. The pressure of the magnetron sputtering equipment was adjusted to 0.4 Pa, the sputtering power was adjusted to 150 W, and sputtering was started. During the sputtering process, argon gas with a purity of >95% was introduced, and the flow rate was controlled to 50 sccm. After the sputtering time reached 10 minutes, the equipment was stopped. The sputtered mass was 1 mg, and a glass fiber diaphragm with an ITO coating was obtained.

[0031] Example 2:

[0032] A circular glass fiber membrane with a diameter of 125 mm and an IZO target with a diameter of 76 mm were placed in the corresponding positions of an existing magnetron sputtering equipment chamber. The pressure of the magnetron sputtering equipment was then adjusted to 0.4 Pa, the sputtering power was adjusted to 150 W, and sputtering began. During the sputtering process, argon gas with a purity of >95% was introduced at a controlled flow rate of 50 sccm. After sputtering for 10 minutes, the equipment was stopped, and the sputtered mass was 1 mg, resulting in a glass fiber membrane with an IZO coating.

[0033] Figure 1-3 Result analysis:

[0034] The surface of the indium-based coating composite diaphragm obtained by magnetron sputtering is evenly distributed with IZO or ITO, which effectively solves the technical problems of particle agglomeration and uneven distribution of traditional diaphragm coatings. The magnetron sputtering method precisely controls the film growth process and realizes the atomic-level epitaxial growth of indium-based oxide 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 on a single glass fiber, which is different from the traditional covering coating and ensures good electrolyte wettability.

[0035] At the same time, the full battery test results show that the prepared GF@ITO and GF@IZO composite membranes show excellent cycle stability: GF@ITO membrane -1 The GF@IZO membrane showed a capacity retention rate of 90.20% after 5000 cycles at a current density of 2Ag. -1 At a current density of 1.5 GHz, it exhibited a capacity retention rate of 86.58% after 5,000 cycles, far exceeding the performance of GF diaphragm. This performance breakthrough stems from the dual advantages of uniform coating construction:

[0036] Interface regulation mechanism: The uniformly distributed IZO / ITO coating provides a high density of zinc-affinity active sites, which significantly reduces the nucleation overpotential of zinc ions on the electrode surface and promotes uniform zinc deposition / stripping behavior.

[0037] Conductive network optimization: The continuous indium-based oxide coating forms an in-plane conductive network inside the diaphragm. Finite element simulation confirms that this network can effectively reduce the uneven distribution of the electric field in the diaphragm plane, inhibit the local current concentration phenomenon under high current density, and thus avoid the directional growth of zinc dendrites.

[0038] Compared with traditional glass fiber separators, the composite separator prepared by this invention exhibits lower Coulombic efficiency decay over long cycles. Furthermore, due to the unique electronic conductivity of the indium-based coating, the ionic conductivity of the composite separator is significantly improved compared to traditional separators, effectively reducing the internal resistance of the battery. Furthermore, the zinc-philic coating significantly inhibits dendrite growth by optimizing zinc ion deposition behavior, achieving a more uniform zinc anode interface. These performance characteristics demonstrate the key role of a uniform indium-based coating in improving conductivity and optimizing zinc deposition behavior.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An indium-based coating composite diaphragm for an aqueous zinc ion battery, characterized in that: A DC magnetron sputtering method is used to sputter an indium-based oxide target onto a base glass fiber diaphragm in a vacuum chamber to obtain an indium-based coating composite diaphragm for an aqueous zinc ion battery, comprising the following steps: (1) Using a UV light cleaning machine to clean the glass fiber diaphragm, the glass fiber diaphragm is placed in the magnetron sputtering chamber; (2) placing the indium-based oxide target into a 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 parameters of the magnetron sputtering equipment to 150-250W / cm 2 , sputtering time is 1 to 15 min and sputtering pressure is 0.2 to 1.0 Pa; (5) operating the equipment to sputter indium-based oxide on the glass fiber separator to produce an indium-based zinc ion battery separator; The indium-based oxide target in step (2) is an indium zinc oxide target or an indium tin oxide target, and the sputtering mass of the indium-based oxide is 1 to 1.22 mg.

2. The indium-based coating composite diaphragm for aqueous zinc ion batteries according to claim 1, characterized in that: The glass fiber diaphragm described in step (1) is GF / D.

3. The indium-based coating composite diaphragm for aqueous zinc ion batteries according to claim 1, characterized in that: Step (1) uses a UV light cleaning machine to clean the glass fiber diaphragm for 10 to 15 minutes.

4. The indium-based coating composite diaphragm for aqueous zinc ion batteries according to claim 1, characterized in that: The pre-sputtering time in step (2) is 0.5 to 3 minutes, and the pre-sputtering power density is 150 to 250 W / cm 2 .

5. The indium-based coating composite diaphragm for aqueous zinc ion batteries according to claim 1, characterized in that: During the sputtering process in step (4), argon gas with a purity greater than 95% is introduced, and the flow rate is controlled to be 50-60 sccm after the argon gas is introduced.

6. An aqueous zinc ion battery indium-based coating composite membrane according to claim 1, wherein the aqueous zinc ion battery indium-based coating composite membrane is used for an aqueous zinc ion battery.

7. An aqueous zinc ion battery indium-based coating composite diaphragm according to claim 6, wherein the aqueous zinc ion battery is used in deep-sea energy storage batteries.

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