Preparation process of heterogeneous metal interface material for aqueous zinc battery

Abstract

The invention belongs to the technical field of water-based rechargeable zinc ion batteries, and particularly relates to a preparation process of a heterogeneous metal interface material for a water-based zinc battery, which comprises the following steps: S1, polishing a zinc foil to remove impurities, and cutting the zinc foil into a Zn wafer with the diameter of 12mm; s2, sequentially putting the Zn wafer into an HCl solution, deionized water, acetone and ethanol for cleaning, and drying for later use; s3, BiCl3 is dissolved in an ethylene glycol solvent, and a spraying solution is prepared through stirring; s4, uniformly spraying the spraying solution on the surface of the Zn wafer to prepare a sample; and S5, cleaning the sample with ethanol to remove residual reactants, and drying at 60 DEG C to prepare the Bi-Zn heterogeneous metal interface material. Compared with an existing Zn electrode, the Bi (at) Zn heterogeneous metal interface material prepared through the method is remarkably improved in the aspects of structure, chemical performance and electrochemical performance, zinc dendrites can be effectively inhibited, the interface stability is improved, and the service life of a battery is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of aqueous rechargeable zinc ion batteries, and in particular relates to a preparation process of a heterogeneous metal interface material for aqueous zinc batteries. Background Art

[0002] Aqueous zinc-ion batteries (Zn-ion batteries) hold broad application prospects in energy storage due to their high theoretical capacity, intrinsic safety, environmental friendliness, and low cost. However, the metallic Zn anode is susceptible to hydrogen evolution side reactions, dendrite growth, and volume expansion in aqueous electrolytes, resulting in poor thermodynamic stability and electrochemical kinetics, severely limiting its commercial application.

[0003] Current research mainly alleviates the above problems by constructing an interface protective layer, electrolyte regulation, electrode structure design, etc. For example, existing patents (such as application numbers CN119208775A and CN117995972A) propose to coat a carbon nitride coating and a zinc titanate coating on the surface of the Zn sheet in sequence to improve its stability, but under high-rate cycling or long-term operation, the protective layer is prone to failure due to volume stress cracking. In addition, some metal materials such as Ag, Au, Cu, etc. are used to guide Zn nucleation, but their high cost, poor thermodynamic stability or hydrogen evolution catalytic effect limit their practical application. Therefore, it is urgent to develop a heterogeneous metal interface material with chemical stability, strong zinc affinity and excellent mechanical properties to effectively inhibit zinc dendrites, improve interface stability and extend battery life. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a process for preparing a heterogeneous metal interface material for an aqueous zinc battery, comprising the following steps:

[0005] S1. Polishing a 100 μm thick, 99.99% pure zinc foil to remove impurities and cutting it into 12 mm diameter Zn discs.

[0006] S2. Wash the Zn disc in HCl solution, deionized water, acetone, and ethanol in sequence, and dry it for later use.

[0007] S3, dissolving BiCl3 in 20 mL of ethylene glycol solvent to prepare a transparent and uniform spray solution at room temperature with continuous stirring;

[0008] S4, spraying the spray solution evenly on the surface of the Zn wafer using an atomizing sprayer at room temperature for 20 minutes to prepare a sample;

[0009] S5. The sample was washed with ethanol to remove residual reactants, and dried at 60° C. to obtain a Bi@Zn heterogeneous metal interface material.

[0010] Optionally, in step S2, the mass fraction of the HCl solution is 12%.

[0011] Optionally, in step S3, the molar concentration of BiCl3 is 0.1 mol / L.

[0012] Optionally, in step S3, Bi 3+ The diffusion coefficient in ethylene glycol solvent is 3.2×10 -6 cm 2 / s.

[0013] Optionally, in step S4, the atomization focus is kept at the center of the Zn disc during the spraying process.

[0014] Optionally, in step S5, the thickness of the interface layer of the Bi@Zn heterogeneous metal interface material is 3 μm.

[0015] The beneficial effects of the present invention are: the Bi@Zn heterogeneous metal interface material prepared by the above preparation process has significantly improved structural, chemical and electrochemical properties compared with the existing Zn electrode:

[0016] (1) Corrosion inhibition: The corrosion current density is significantly reduced, nearly 90% less than that of bare Zn, effectively reducing the hydrogen evolution side reaction.

[0017] (2) Improved thermodynamic stability: The Bi coating layer exists stably in weakly acidic conditions without obvious corrosion or passivation.

[0018] (3) Improved stability: The Bi layer effectively alleviates the problem of protective layer fracture caused by Zn volume expansion, and the cycle life is increased to more than 2000h. 2 Under these conditions, the Bi@Zn electrode maintains low polarization (45 mV) and excellent high-rate cycling performance, which is significantly better than existing protective coatings.

[0019] (4) Excellent zinc affinity: The CV curves of different symmetrical batteries were tested. The symmetrical Bi@Zn battery showed a larger integrated peak area and higher current intensity than the bare Zn battery, proving that Zn 2+ The enhanced accumulation of Bi and improved plating / stripping kinetics, which are beneficial to activate more nucleation sites for uniform Zn deposition, indicate that Bi sites reduce the Zn nucleation energy barrier and promote uniform nucleation and deposition.

[0020] (5) Enhanced electrochemical performance: Zn / / Cu asymmetric battery at 10 mA / cm 2 The short circuit failure occurred after 900 cycles, and the polarization voltage was 80mV. Zn / / Bi@Cu asymmetric battery, at 10mA / cm 2 The polarization voltage remained at 55 mV after more than 4700 cycles, and no obvious zinc dendrite formation or electrode short circuit was observed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and examples.

[0022] Figure 1 It is a flow chart of the preparation process of the present invention.

[0023] Figure 2 Bi of the present invention 3+ Comparison of diffusion coefficients in different solvents.

[0024] Figure 3 This is an SEM image of the cross section of the Bi@Zn heterogeneous negative electrode of the present invention.

[0025] Figure 4 This is a comparison diagram of the Tafel curves of Bi@Zn of the present invention and bare Zn.

[0026] Figure 5 This is a voltage-time comparison diagram of the Bi@Zn and Zn / / Zn symmetric batteries of the present invention under long cycle conditions.

[0027] Figure 6 1.0mV s -1 CV curve of the symmetrical battery below.

[0028] Figure 7 This is a comparison chart of the coulombic efficiency-cycle number of the Zn / / Bi@Cu and Zn / / Cu asymmetric batteries of the present invention under long cycle conditions.

[0029] Figure 8 This is a comparison diagram of the current density-overpotential of the Zn / / Bi@Cu and Zn / / Cu asymmetric batteries of the present invention. DETAILED DESCRIPTION

[0030] The present invention is described below in conjunction with the accompanying drawings and specific embodiments of the present invention. The description herein is only used to explain the present invention and is not intended to limit the present invention. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without creative work based on all other embodiments obtained in the present invention should be included in the scope of protection of the present invention.

[0031] Example

[0032] Combine Figure 1As shown, the preparation process of the heterogeneous metal interface material for aqueous zinc batteries provided by the embodiment of the present invention includes the following steps: S1, polishing a zinc foil with a thickness of 100 μm and a purity of 99.99% to remove impurities, and cutting it into a Zn disc with a diameter of 12 mm; S2, placing the Zn disc into a 12% mass fraction HCl solution, deionized water, acetone, and ethanol in turn for cleaning, drying and setting aside; S3, dissolving BiCl3 with a molar concentration of 0.1 mol / L in 20 mL of ethylene glycol solvent, as shown in FIG. Figure 2 As shown, where Bi 3+ The diffusion coefficient in ethylene glycol solvent is 3.2×10 -6 cm 2 / s, and then a transparent and uniform spray solution is prepared at room temperature and under continuous stirring conditions; S4, the above spray solution is evenly sprayed on the surface of the Zn disc through an atomizing sprayer at room temperature for 20 minutes to prepare a sample, and the atomization focus is kept at the center of the Zn disc during the spraying process; S5, the above sample is washed with ethanol to remove residual reactants, and dried at 60°C to prepare a Bi@Zn heterogeneous metal interface material, that is, a Bi@Zn negative electrode is prepared, such as Figure 3 As shown, the thickness of the interface layer of the Bi@Zn heterogeneous metal interface material is 3μm.

[0033] Comparative Example

[0034] The difference between this comparative example and the embodiment is that the polished Zn sheet is processed according to the above steps S1 and S2, and steps S3 to S5 are not performed to prepare a comparative sample.

[0035] The Bi@Zn negative electrode prepared in the embodiment and the comparative sample prepared in the comparative example were subjected to Bi@Zn symmetric battery test and Zn / / Zn symmetric battery test respectively:

[0036] like Figure 4 As shown in the figure, the positive corrosion potential of Bi@Zn anode (0.965 V) is higher than that of bare Zn anode (0.971 V), which indicates that the susceptibility to corrosion side reactions is lower due to the barrier effect of Bi protective layer. More importantly, the corrosion current of Bi@Zn anode (2.22 μA cm -2 ) is only for the bare Zn anode (18.92 μA cm -2 ), indicating that the corrosion rate of Bi@Zn anode is much lower.

[0037] like Figure 5 As shown, Zn / / Zn symmetric battery test, 10mA / cm 2 After about 280 cycles, a short circuit occurred and the polarization voltage increased to over 180mV. Bi@Zn symmetric battery test, 10mA / cm 2There was no short circuit after 2000 cycles, and the polarization voltage was 45mV.

[0038] like Figure 6 As shown, the symmetric Bi@Zn battery shows a larger integrated peak area and higher current intensity than that of bare Zn, proving that Zn 2+ The enhanced accumulation of Bi and improved plating / stripping kinetics, which are beneficial to activate more nucleation sites for uniform Zn deposition, indicate that Bi sites reduce the Zn nucleation energy barrier and promote uniform nucleation and deposition.

[0039] like Figure 7-8 As shown, the Zn / / Cu asymmetric battery is at 10 mA / cm 2 The short circuit failure occurred after 900 cycles, and the polarization voltage was 80mV. Zn / / Bi@Cu asymmetric battery, at 10mA / cm 2 The polarization voltage remained at 55 mV after more than 4700 cycles, and no obvious zinc dendrite formation or electrode short circuit was observed.

[0040] While the embodiments of the present invention have been described above, the above description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A process for preparing heterogeneous metal interface materials for aqueous zinc batteries, characterized by: The following steps are involved: S1. Polishing a 100 μm thick, 99.99% pure zinc foil to remove impurities and cutting it into 12 mm diameter Zn discs. S2. Wash the Zn disc in HCl solution, deionized water, acetone, and ethanol in sequence, and dry it for later use. S3, dissolving BiCl3 in 20 mL of ethylene glycol solvent to prepare a transparent and uniform spray solution at room temperature with continuous stirring; S4, spraying the spray solution evenly on the surface of the Zn wafer using an atomizing sprayer at room temperature for 20 minutes to prepare a sample; S5. The sample was washed with ethanol to remove residual reactants, and dried at 60° C. to obtain a Bi@Zn heterogeneous metal interface material.

2. The preparation process according to claim 1, wherein: In step S2, the mass fraction of the HCl solution is 12%.

3. The preparation process according to claim 1, wherein: In step S3, the molar concentration of BiCl3 is 0.1 mol / L.

4. The preparation process according to claim 1, wherein: In step S3, Bi 3+ The diffusion coefficient in ethylene glycol solvent is 3.2×10 -6 cm 2 / s.

5. The preparation process according to claim 1, wherein: In step S4, the atomization focus is kept at the center of the Zn disc during the spraying process.

6. The preparation process according to claim 1, wherein: In step S5 , the thickness of the interface layer of the Bi@Zn heterogeneous metal interface material is 3 μm.

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