Preparation of In-C-Al electrode with double-layer artificial protection interface and application of In-C-Al electrode in aqueous aluminum ion battery

Abstract

The invention provides preparation of an In-C-Al electrode with a double-layer artificial protection interface and application of the In-C-Al electrode in a water-based aluminum ion battery, and belongs to the field of water-based aluminum ion batteries. The In-C (at) Al electrode with the double-layer artificial protection interface is composed of physical coating activated carbon (AC) on the inner layer and electrochemical deposition indium (In) particles on the outer layer, wherein the diameter range of the In particles is 2-9 m. The indium (In) particles on the outer layer form a geometrical shape similar to cobblestones, can provide abundant nucleation sites for aluminum deposition, and promote rapid transmission of ions and efficient transfer of charges at the same time. The inner active carbon (AC) layer serves as a physical coating, can effectively prevent direct contact between the metal anode and electrolyte, plays a buffering role, maintains the stability of the electrode structure, inhibits passivation of the aluminum anode and reduces the self-corrosion rate.

Description

[0001] The invention belongs to the field of aqueous aluminum ion batteries and relates to preparation of an In-C@Al electrode with a double-layer artificial protection interface and application of the same in aqueous aluminum ion batteries. Background Art

[0002] With the gradual depletion of fossil fuel reserves and the intensification of global environmental problems, the development of green and sustainable energy storage technologies has become a research hotspot. Among them, rechargeable battery systems with low cost, high safety and long cycle life have attracted much attention. Due to their high energy density, lithium-ion batteries (LIBs) have made great progress and dominated the market, but they still have common safety issues caused by flammable organic electrolytes and high production costs due to lithium scarcity. These problems have hindered the large-scale application of lithium-ion batteries, prompting researchers to explore alternative energy storage devices with low cost, high safety and long cycle life.

[0003] In recent years, multivalent ion batteries based on zinc ions, magnesium ions and aluminum ions are considered to be promising alternatives to lithium-ion batteries. These multivalent ions have higher charge density, smaller ionic radius and lower deposition potential, and the multivalent ion batteries involved can use water as electrolyte to improve safety and optimize performance. Among them, aqueous aluminum-ion batteries have become the focus of research because aluminum is the most abundant metal element in the earth's crust, has low cost and high safety, and the redox process of aluminum involves three-electron transfer and has high theoretical specific capacity. However, aluminum metal, a common negative electrode material for aqueous aluminum-ion batteries, faces corrosion and passivation problems in aqueous solution. These fatal defects will seriously damage the cycle stability and electrochemical performance of the aluminum negative electrode. Therefore, it is urgent to explore feasible methods to make the aluminum negative electrode work stably in aqueous solution.

[0004] Based on the above analysis, this patent proposes a method for preparing an In-C@Al electrode with a double-layer artificial protective interface. Specifically, a double-layer artificial protective interface is developed on the negative electrode surface of aluminum (Al) foil, which consists of an inner layer of physically coated activated carbon (AC) and an outer layer of electrochemically deposited indium (In) particles (diameter ranges from 2 to 9 µm). The outer indium particle layer presents a pebble-like geometry with a large amount of space between the particles, which provides abundant nucleation sites for uniform aluminum deposition. In addition, the porous structure of the indium (In) metal particle layer can effectively adapt to volume changes during aluminum deposition / stripping, while the low binding energy characteristics between In and Al³⁺ ions further promote charge transfer. The activated carbon (AC) layer acts as a physical barrier to isolate the metal anode from direct contact with the electrolyte, thereby inhibiting the passivation reaction and reducing the self-corrosion rate. In addition, the AC layer also has a buffering effect, which can relieve the lattice stress between the intrinsic aluminum foil and the indium metal particle layer, thereby helping to maintain the stability of the electrode structure. The double-layer artificial protective interface can provide the possibility for the preparation of aluminum ion battery negative electrodes with long-term stable cycles. Summary of the invention

[0005] The specific steps of the preparation method of an In-C@Al electrode with a double-layer artificial protection interface in the present invention are as follows: 1. The aluminum foil (10 cm × 20 cm) was mechanically polished (sandpaper mesh ≥ 2000), ultrasonically cleaned with ethanol (frequency 40 kHz, duration 10 min) and vacuum dried (60°C, 12 h). 2. Mix activated carbon and PVDF in a certain mass ratio, add an appropriate amount of NMP and stir for 12 hours to form a viscous slurry; 3. The prepared slurry was scraped onto the treated aluminum foil and vacuum dried at 60°C for 12 hours to obtain C@Al; 4. Punch C@Al into a small disc with a diameter of 12 mm, then cover its back with an insulating kapton film, use it as a working electrode, and use a platinum sheet as a counter electrode. Perform electrochemical treatment in an electrolyte of a certain concentration to produce a high-performance In-C@Al negative electrode.

[0006] The above-mentioned preparation of a high-performance In-C@Al negative electrode, wherein, preferably, the mass ratio of activated carbon to PVDF in step (2) is 9:1; the electrochemical treatment method described in step (4) is a constant voltage deposition method, the voltage is 3 V, the deposition time is 30 min, and the electrolyte is an equal volume mixed aqueous solution of 0.5 mol / L Al2(SO4)3·18H2O and 0.5 mol / L InCl3.

[0007] Beneficial effects of the present invention The preparation method of the material is simple and low-cost, and at the same time provides a new negative electrode material for aqueous aluminum ion batteries. The unique double-layer artificial protective interface of the In-C@Al electrode provided by the present invention provides a large number of nucleation sites for uniform deposition of aluminum, and can effectively prevent direct contact between the metal negative electrode and the electrolyte, thereby inhibiting passivation and corrosion. Compared with pure aluminum metal negative electrodes, the symmetrical battery prepared by the In-C@Al negative electrode provided by the present invention and the aqueous aluminum ion full battery have better electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 , preparation flow chart of In-C@Al electrode with double-layer artificial protective interface.

[0009] Figure 2 , XRD pattern of In-C@Al electrode with double-layer artificial protective interface.

[0010] Figure 3 , Top-down SEM image and optical photograph of the In-C@Al electrode with a double-layer artificial protective interface.

[0011] Figure 4 , Energy dispersive X-ray spectroscopy (EDX) elemental map of the cross section of the In-C@Al electrode with a double-layer artificial protection interface.

[0012] Figure 5 The symmetric battery composed of In-C@Al electrodes with a double-layer artificial protection interface was −2 The nucleation overpotential at .

[0013] Figure 6 , electrochemical impedance spectroscopy (EIS) of a symmetric battery composed of In-C@Al electrodes with a double-layer artificial protective interface. Figure 7 The symmetric battery composed of In-C@Al electrodes with a double-layer artificial protection interface was tested at a current density of 0.05 mA cm -2 Long cycle performance diagram when .

[0014] Figure 8 The aqueous aluminum ion full battery composed of In-C@Al electrode with double-layer artificial protection interface and commercial Mn3O4 was tested at 0.1mV s -1 Cyclic voltammetry (CV) tests were performed.

[0015] Fig. 9 , electrochemical impedance spectroscopy (EIS) of an aqueous aluminum ion full battery consisting of an In-C@Al electrode with a double-layer artificial protective interface and commercial Mn3O4.

[0016] Fig.10 The aqueous aluminum ion full battery composed of In-C@Al electrode with double-layer artificial protection interface and commercial Mn3O4 was used at a current density of 1 A g -1 The long cycle performance diagram below. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example

[0018] The preparation of the In-C@Al electrode with a double-layer artificial protection interface in this embodiment is carried out according to the following steps: A. First, aluminum foil (10 cm × 20 cm) was polished with sandpaper to remove the surface oxide layer, and then ultrasonically cleaned with ethanol to remove surface impurities; B. Mix activated carbon and PVDF in a mass ratio of 9:1, add an appropriate amount of NMP and stir for 12 hours to form a viscous slurry; C. The prepared slurry was coated onto the treated aluminum foil by knife coating and vacuum dried at 60°C for 12 hours to obtain C@Al; D. Punch the prepared C@Al into small discs with a diameter of 12 mm, and then cover the back side with an insulating kapton film; E. The treated C@Al was used as the working electrode and the platinum sheet as the counter electrode. At room temperature, an equal volume mixed aqueous solution of 0.5 mol / L Al2(SO4)3·18H2O and 0.5 mol / L InCl3 was used as the electrolyte. In a conventional two-electrode cell, the In-C@Al electrode was obtained by electrochemical treatment at a constant voltage of 3V for 30 minutes. The prepared In-C@Al electrode was rinsed with deionized water to remove the residual electrolyte and then naturally air-dried at room temperature. Example

[0019] The preparation of the In-C@Al electrode with a double-layer artificial protection interface in this embodiment is carried out according to the following steps: A. First, aluminum foil (10 cm × 20 cm) was polished with sandpaper to remove the surface oxide layer, and then ultrasonically cleaned with ethanol to remove surface impurities; B. Mix activated carbon and PVDF in a mass ratio of 9:1, add an appropriate amount of NMP and stir for 12 hours to form a viscous slurry; D. Punch the prepared C@Al into small discs with a diameter of 12 mm, and then cover the back side with an insulating kapton film; E. The treated C@Al was used as the working electrode and the platinum sheet as the counter electrode. At room temperature, an equal volume mixed aqueous solution of 0.5 mol / L Al2(SO4)3·18H2O and 0.5 mol / L InCl3 was used as the electrolyte. In a conventional two-electrode cell, the In-C@Al electrode was obtained by electrochemical treatment at a constant voltage of 3V for 25 minutes. The prepared In-C@Al electrode was rinsed with deionized water to remove the residual electrolyte and then air-dried at room temperature. Example

[0020] The preparation of the In-C@Al electrode with a double-layer artificial protection interface in this embodiment is carried out according to the following steps: A. First, aluminum foil (10 cm × 20 cm) was polished with sandpaper to remove the surface oxide layer, and then ultrasonically cleaned with ethanol to remove surface impurities; B. Mix activated carbon and PVDF in a mass ratio of 9:1, add an appropriate amount of NMP and stir for 12 hours to form a viscous slurry; C. The prepared slurry was coated onto the treated aluminum foil by knife coating and vacuum dried at 60°C for 12 hours to obtain C@Al; D. Punch the prepared C@Al into small discs with a diameter of 12 mm, and then cover the back side with an insulating kapton film; E. The treated C@Al was used as the working electrode and the platinum sheet as the counter electrode. At room temperature, an equal volume mixed aqueous solution of 0.5 mol / L Al2(SO4)3·18H2O and 0.5 mol / L InCl3 was used as the electrolyte. In a conventional two-electrode cell, the In-C@Al electrode was obtained by electrochemical treatment at a constant voltage of 3V for 35 minutes. The prepared In-C@Al electrode was rinsed with deionized water to remove the residual electrolyte and then naturally air-dried at room temperature.

[0021] Morphological and structural characterization of materials Figure 2 This is the XRD diagram of the In-C@Al electrode obtained in the present invention, and the diffraction peak corresponding to metal In (JCPDS 05-0642) can be clearly observed. Figure 3 The optical photo and scanning electron microscope (SEM) image of the In-C@Al electrode show that the metal In is evenly and tightly fixed on the activated carbon (AC) layer, and there are a lot of gaps between the In particles, just like pebbles evenly distributed on the river bank. This structure not only provides abundant nucleation sites for aluminum deposition, but also adapts to the volume change during aluminum deposition / stripping. Provide more nucleation sites. Figure 4The energy dispersive X-ray spectroscopy (EDX) elemental mapping further confirmed the uniform distribution of the In metal protective layer and the AC coating on the aluminum foil surface. The thickness of the In metal protective layer is about 40 μm.

[0022] Electrochemical performance test results of materials The symmetric battery with the In-C@Al electrode with a double-layer artificial protection interface prepared in Example 1 was operated at 1 mAcm −2 Nucleation overpotential test was carried out at a current density of The symmetric cell with the In-C@Al electrode with a double-layer artificial protection interface prepared in Example 1 was charged at 0.05 mA cm -2 Current density for long cycle performance test; The aqueous aluminum ion full battery composed of the In-C@Al electrode with a double-layer artificial protection interface prepared in Example 1 and commercial Mn3O4 was tested at 0.1 mV s -1 Cyclic voltammetry (CV) tests were performed under The aqueous aluminum ion full battery composed of the In-C@Al electrode with a double-layer artificial protection interface prepared in Example 1 and commercial Mn3O4 was subjected to electrochemical impedance spectroscopy (EIS) test in the frequency range of 100000 Hz to 0.01 Hz; The aqueous aluminum ion full battery composed of the In-C@Al electrode with a double-layer artificial protection interface prepared in Example 1 and commercial Mn3O4 was used at 1 A g -1 The long cycle performance test was carried out at a current density of 1.54 W.

[0023] according to Figure 5 From the constant current nucleation overpotential distribution diagram, it can be seen that the nucleation overpotential of In-C@Al is only 3.4 mV, while the nucleation overpotential of bare Al is 74.1 mV. This indicates that In-C@Al achieves a lower nucleation barrier and more uniform Al nucleation. Figure 6 The impedance comparison of a bare aluminum symmetric cell and a symmetric cell with an In-C@Al electrode with a double-layer artificial protection interface. The charge transfer resistance Rct of the bare aluminum symmetric cell was determined to be 4238 Ω by equivalent circuit fitting. In comparison, the Rct of the symmetric cell with an In-C@Al electrode with a double-layer artificial protection interface was 47.6 Ω. This proves that the In-C@Al electrode with a double-layer artificial protection interface can improve ion migration and charge transfer rates. Figure 7 For two symmetric cells at 0.05 mA cm -2Long cycle performance under current density. The overpotential of the bare aluminum symmetric cell reached 125 mV in the initial stage of the cycle. As the cycle time increased, the overpotential gradually increased and reached 1000 mV at about 200 h of cycling. In contrast, the In-C@Al battery exhibited stable aluminum deposition / stripping behavior with a cycle time of more than 2000 h and an average overpotential of ~5 mV. This shows that the prepared double-layer artificial protective interface In-C plays an important role in improving the electrochemical reversibility of the Al electrode. Figure 8 The aqueous aluminum ion full battery composed of bare aluminum and commercial Mn3O4 and the aqueous aluminum ion full battery composed of In-C@Al electrode with double-layer artificial protection interface and commercial MnO2 were tested in the voltage range of 0-1.9 V and the scan rate was 0.1 mV s −1 The obtained CV test curves are compared. It can be seen that the CV curve of the In-C@Al||Mn3O4 battery has a clearer profile, and the redox peak position moves toward the positive potential relative to the Al||Mn3O4 battery, and the peak current is also higher. It proves that the battery with the In-C@Al electrode with a double-layer artificial protective interface has superior charge transfer kinetics and electrochemical reactivity. This can be attributed to the reduced charge transfer resistance given to In-C@Al by the double-layer artificial protective interface In-C, such as Fig. 9 The impedance comparison of aqueous aluminum ion full battery composed of bare aluminum and commercial Mn3O4 and aqueous aluminum ion full battery composed of In-C@Al electrode with double-layer artificial protection interface and commercial Mn3O4 can also prove this. Fig.10 The results show that the aqueous aluminum-ion full battery composed of bare aluminum and commercial Mn3O4 and the aqueous aluminum-ion full battery composed of In-C@Al electrode with double-layer artificial protection interface and commercial Mn3O4 have a good performance at 1 A g -1 The long cycle performance diagram at a current density of 2.5 ... -1 The battery has excellent capacity, with a capacity retention rate of 90% and no obvious CE drop. However, the capacity of the aqueous aluminum ion full battery composed of bare aluminum and commercial Mn3O4 dropped rapidly after 100 cycles, and eventually the battery failed and could not provide capacity. This may be due to the rupture of the battery and its inability to work due to dendrite growth and violent side reactions on the Al anode, which further illustrates the advantages of the double-layer artificial protective interface In-C. The In-C@Al electrode with a double-layer artificial protective interface can be used as the negative electrode of an aqueous aluminum ion battery and has good application prospects in the field of aqueous batteries. The method of the present invention has wide applicability and can be extended to other energy storage battery systems, providing a new approach and concept for improving the electrochemical properties and structural stability of metal electrodes.

[0024] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for preparing an In-C@Al electrode with a double-layer artificial protective interface, characterized in that: The following steps are involved: (1) Aluminum foil (10 cm × 20 cm) was mechanically polished (sandpaper grit ≥ 2000), ultrasonically cleaned with ethanol (frequency 40 kHz, duration 10 min), and vacuum dried (60 °C, 12 h). (2) Mix activated carbon and PVDF in a certain mass ratio, add an appropriate amount of N-methylpyrrolidone (NMP) and stir for 12 hours to form a viscous slurry; (3) applying the slurry prepared in step (2) to the aluminum foil treated in step (1) by scraping, and vacuum drying at 60° C. for 12 hours to obtain C@Al; (4) The C@Al prepared in step (3) was punched into a small disc with a diameter of 12 mm, and then its back was covered with an insulating kapton film and used as a working electrode, and a platinum sheet was used as a counter electrode. Electrochemical treatment was performed in an electrolyte of a certain concentration to obtain a high-performance In-C@Al negative electrode.

2. The preparation method according to claim 1, characterized in that: The mass ratio of activated carbon to PVDF in step (2) is 9:

1.

3. The preparation method according to claim 1, characterized in that: The electrolyte described in step (4) is an equal volume mixed aqueous solution of 0.5 mol / L Al2(SO4)3·18H2O and 0.5 mol / L InCl3.

4. The preparation method according to claim 1, characterized in that: The electrochemical treatment method described in step (4) is a constant voltage deposition method with a voltage of 3 V and a deposition time of 30 min.

5. Application of the In-C@Al electrode with a double-layer artificial protective interface according to claim 1 as a negative electrode of an aqueous aluminum ion battery.

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