Preparation method of BiSb bimetallic coating zinc electrode and application of BiSb bimetallic coating zinc electrode in aqueous zinc ion battery

Abstract

The invention relates to a preparation method of a BiSb bimetallic coating zinc electrode and application of the BiSb bimetallic coating zinc electrode in an aqueous zinc ion battery. Cleaning of a negative electrode material: placing the zinc negative electrode material in an organic solvent for ultrasonic cleaning; adding BiCl3 and SbCl3 into the organic solution, and stirring to obtain a replacement solution; and taking the zinc negative electrode material as a working electrode, and placing the working electrode in the replacement liquid to obtain the modified zinc electrode material. BiSb bimetallic is successfully introduced to the Zn foil surface (Zn coated BiSb) through a double replacement reaction to provide abundant nucleation sites and increase the hydrophilicity of the Zn surface, so that the deposition behavior of Zn < 2 + > is adjusted, the uniform growth of Zn is promoted, and the cycle performance and stability of a symmetric battery and a total battery are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of zinc ion battery negative electrode material preparation, and particularly relates to a BiSb bimetallic coating zinc electrode preparation method and application thereof in aqueous zinc ion batteries. BACKGROUND

[0002] Aqueous zinc ion batteries (AZIBs) are considered as a promising candidate for large-scale energy storage in the post-lithium era due to their low cost, high safety, environmental friendliness, and high theoretical capacity (820 mAh g -1 and 5855 mAh cm -3 ). However, the main challenge faced by AZIBs is uncontrolled dendrite growth, which is derived from the limited nucleation sites on the Zn negative electrode surface and the non-uniform deposition of the electrode during repeated cycles, which can form "dead zinc" and pierce the separator to cause battery short circuits. At the same time, due to the low standard electrode potential of Zn 2+ / Zn, and direct contact at the electrode / electrolyte interface in weak acid electrolyte, which can cause side reactions such as electrochemical corrosion and hydrogen evolution, seriously hindering the practical application of AZIBs.

[0003] With the deepening of research, researchers found that the metal Zn negative electrode has problems such as poor thermal stability and slow electrochemical kinetics in aqueous solution, which seriously hinders practical application. In order to solve the above problems, various zincophilic surface modification strategies have been developed, including inorganic non-metallic materials, organic polymers, metal materials or alloy solid solutions, to promote the reversible deposition / stripping behavior of Zn, although these strategies have made great progress, but in the long-term cycle process, it is still difficult to continuously adjust the deposition / stripping behavior of Zn. Therefore, it is essential to fundamentally improve the kinetic process of Zn 2+ .

[0004] Zincophilic metals introduce initial nucleation sites of Zn metal and are applied to improve the electrochemical performance of Zn negative electrode in subsequent deposition. For example, Au, Ag, Cu, Sb, Sn, Ni, Co, Bi and other zincophilic metals can form a metal layer at the interface of the electrode, which enhances the interaction, reduces the nucleation energy barrier, and uniformly distributes the ion and electric field. However, different single-element zincophilic metals will bring different challenges. For example, the high cost and poor ductility of Au and Ag will hinder further development; Sn, Ni, Co have poor electrochemical stability in weak acid electrolyte, and Cu can catalyze water decomposition and exacerbate the hydrogen evolution problem caused by poor thermodynamic stability. At present, the physicochemical properties of the metal itself of the single metal interface layer have more or less shortcomings, which further restrict the development of research, therefore, it is particularly important to explore hetero-metal interface protection layer to further improve the electrochemical performance of Zn negative electrode. SUMMARY

[0005] The application provides a BiSb bimetallic coating zinc electrode preparation method and application in an aqueous zinc ion battery.

[0006] The application provides the technical scheme adopted is: A BiSb bimetallic coating zinc electrode material preparation method, the method comprises the following steps: (1) cleaning of the negative electrode material: the zinc negative electrode material is ultrasonically cleaned in an organic solvent; (2) preparation of the displacement solution: BiCl3 and SbCl3 are added to an organic solution, and stirring is performed to obtain the displacement solution; (3) the zinc negative electrode material obtained in step (1) is used as a working electrode and is placed in the displacement solution obtained in step 2) for a period of time to obtain a modified zinc electrode material. Preferably, the organic solvent in step (1) is anhydrous ethanol, and the mass percentage is 75-99.5 %, preferably, the mass percentage of anhydrous ethanol is 99.5 %.

[0007] Preferably, the organic solvent in step (2) is anhydrous ethanol, and the mass percentage is 99.5 %, and the solid-liquid ratio of BiCl3, SbCl3 and anhydrous ethanol is (0.05-0.15):(0.15-0.25):(110-130) (g / g / mL). Further preferably, the organic solvent in step (2) is anhydrous ethanol, and the mass percentage is 99.5 %, and the solid-liquid ratio of BiCl3, SbCl3 and anhydrous ethanol is 0.100:0.200:120 (g / g / mL). Preferably, the stirring condition temperature in step (2) is 20-30 DEG C, and the stirring duration is 10-14 hours; further preferably, the stirring condition temperature is 25 DEG C, and the stirring duration is 12 hours. Preferably, in step (3), one side of the zinc negative electrode material is pasted with an organic adhesive tape to realize single-side reaction of zinc, and the reaction duration of the zinc negative electrode material in the displacement solution is 1-10 min, further preferably, the displacement duration is 1 min, 3 min, 5 min, 7 min or 10 min, and a modified zinc electrode material is obtained.

[0008] The aqueous zinc ion battery material prepared by the BiSb bimetallic coating zinc electrode material preparation method can be used as a negative electrode material in an aqueous zinc ion battery. The application has the following beneficial effects: 1. The raw materials used in the application have low cost and are environmentally friendly, the displacement reaction preparation method is convenient to operate and is conducive to large-scale production.

[0009] 2. This invention provides a bismuth-antimony bimetallic zinc anode material for aqueous zinc-ion batteries. Compared to bismuth and antimony monometallic layers, the BiSb bimetallic layer is introduced onto the Zn foil surface via a double substitution reaction, accelerating the reaction kinetics of Zn, providing abundant nucleation sites, and simultaneously increasing the hydrophilicity of the Zn surface, thus promoting the rapid transfer kinetics of Zn and regulating the Zn reaction. 2+ The deposition behavior of the BiSb bimetallic layer promotes uniform Zn growth, improving the cycle performance and stability of symmetric and full cells. This invention benefits from the improved Zn deposition behavior on the Zn metal surface by the BiSb bimetallic layer. 2+ The electrochemical kinetics of the process are described. In summary, this work provides a simple and efficient strategy for introducing bimetals into the surface of Zn foil to improve the electrochemical performance of its electrodes. Attached Figure Description

[0010] Figure 1 XPS measurements of Bare Zn, Zn@Bi, Zn@Sb and Zn@BiSb electrodes. a) Full XPS spectrum; b) Fine spectrum of Bi 4f; c) Fine spectrum of Sb 3d; d) Fine spectrum of Zn 2p.

[0011] Figure 2 Cyclic performance of symmetrical cells with Zn@BiSb electrode under different replacement durations.

[0012] Figure 3 Comparison of cycling performance of Bare Zn, Zn@Bi, Zn@Sb and Zn@BiSb electrodes.

[0013] Figure 4 Exchange current density plots and CA curves of Bare Zn and Zn@BiSb electrodes.

[0014] Figure 5 a) Impedance plots of Bare Zn, Zn@Bi, Zn@Sb and Zn@BiSb electrodes; b) CV plots of Bare Zn, Zn@Bi, Zn@Sb and Zn@BiSb electrodes; c) Nucleation overpotential plots of Bare Zn, Zn@Bi, Zn@Sb and Zn@BiSb electrodes.

[0015] Figure 6 Contact angle testing of Bare Zn, Zn@Sb, Zn@Bi and Zn@BiSb electrodes.

[0016] Figure 7 In-situ optical images of Bare Zn and Zn@BiSb electrodes.

[0017] Figure 8A full cell of CNT-MnO2 with Bare Zn and Zn@BiSb electrodes at 1 A g -1 The long-term cycling performance diagram at current density. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, those skilled in the art can obtain the following results without creative effort: Other embodiments are also included within the scope of protection of this invention.

[0019] Example 1 A method for preparing a BiSb bimetallic coated zinc electrode material, the method comprising the following steps: (1) Cleaning and treatment of negative electrode material: Zinc foil is placed in anhydrous ethanol solution, ultrasonically cleaned for 10 min, and then dried in a constant temperature drying oven at 40℃ for 30 min. Then, one side is covered with anti-organic solvent tape, and then cut into 2cm*3cm size for later use. (2) Preparation of replacement solution: Accurately weigh 0.200 g of antimony trichloride and dissolve it in 120 mL of anhydrous ethanol. Stir for 10 min to obtain a clear solution. Then accurately weigh 0.100 g of bismuth trichloride and add it to the solution. Stir at 25℃ for 12 h to obtain the replacement solution. (3) Displacement reaction: The zinc current collector obtained in step (1) is used as the working electrode and immersed in the electroplating solution obtained in step (2). The displacement time is 1 min to prepare the modified zinc electrode. (4) After the displacement reaction is completed, the electrode is removed, and the residual liquid on the surface is rinsed off with deionized water and anhydrous ethanol. Then, it is dried at 60°C for 4 h to obtain the Zn-BiSb-1 modified zinc electrode.

[0020] Example 2 The method and steps are the same as in Example 1, except that the replacement time in step (3) is changed to 3 min to prepare a Zn-ZnSn-3 zinc electrode.

[0021] Example 3 The method and steps are the same as in Example 1, except that the replacement time in step (3) is changed to 5 min to prepare a Zn-ZnSn-5 zinc electrode.

[0022] Example 4 The method and steps are the same as in Example 1, except that the replacement time in step (3) is changed to 7 min to prepare a Zn-ZnSn-7 zinc electrode.

[0023] Example 5 The method and steps are the same as in Example 1, except that the replacement time in step (3) is changed to 10 min to prepare a Zn-ZnSn-10 zinc electrode.

[0024] Example 6 The method and steps are the same as in Example 1, except that 0.200 g of antimony trichloride in step (2) is removed to prepare the Zn@Bi zinc electrode.

[0025] Example 7 The method and steps are the same as in Example 1, except that 0.100 g of bismuth trichloride in step (2) is removed to prepare the Zn@Sb zinc electrode.

[0026] The Zn-BiSb-5 prepared in Example 3 is denoted as Zn@BiSb. It is cut into 12 mm diameter discs to serve as the positive and negative electrodes of the button cell. A 19 mm diameter glass fiber membrane (GF-A, Whatman) is used, and 2 mol / L ZnSO4 is used as the electrolyte. The cells are assembled into button cells under normal conditions and denoted as Zn@BiSb / / Zn@BiSb symmetric cells.

[0027] The Zn-BiSb-5 prepared in Example 3 is denoted as Zn@BiSb and is used as the negative electrode of the button cell. The diameter is 15 mm. The diameter of the CNT-MnO2 electrode disc is 12 mm and is used as the positive electrode. A glass fiber membrane (GF-A, Whatman) with a diameter of 19 mm is used. 2 mol / L ZnSO4 and 0.2 mol / L MnSO4 are used as electrolytes. The button cell is assembled under normal conditions and denoted as Zn@ZnSn / / CNT-MnO2 full cell.

[0028] Comparative Example 1 Zinc foil is used as the positive and negative electrodes of the button cell, a glass fiber separator is used, and 2 mol / L ZnSO4 is used as the electrolyte. The button cell is assembled under normal conditions and is called a Zn / / Zn symmetric cell.

[0029] A button cell was assembled under normal conditions using zinc foil as the negative electrode, MnO2 as the positive electrode, a glass fiber separator, and 2 mol / L ZnSO4 and 0.2 mol / L MnSO4 as electrolytes. This was denoted as a Zn / / CNT-MnO2 full cell.

[0030] Results and Testing: The prepared Zn@BiSb anode material was subjected to X-ray photoelectron spectroscopy analysis, symmetric cell cycle life testing, scanning electron microscopy analysis, contact angle testing, electrochemical impedance spectroscopy testing, full cell life and retention rate testing, CA testing, and CV testing. The results are as follows: Figures 1-8 As shown.

[0031] Example 8 The Zn@BiSb, Zn@Bi, Zn@Sb, and Bare Zn electrodes prepared in Examples 1, 6, 7, and Comparative Example 1 were subjected to X-ray photoelectron spectroscopy (XPS) testing. Figure 1 As shown in Figure a, Bare Zn and other samples exhibited 2p, 3s, and 3d peaks of Zn metal. The Zn@Sb anode showed 3p, 3d, and 4d peaks of Sb metal, indicating the presence of Sb metal on the Zn surface and demonstrating the successful preparation of Zn@Sb. The Zn@Bi anode showed 4p, 4d, 4f, and 5d characteristic peaks of Bi metal, indicating the presence of Bi on the Zn metal surface and demonstrating the successful preparation of Bi. The Zn@BiSb anode surface simultaneously showed characteristic peaks of both Bi and Sb metals, indicating the presence of Bi and Sb metals on the Zn metal surface. Figure 1 Figures b and c show the high-resolution XPS spectra of Bi 4f and Sb 3d. Compared with Zn@Bi, the 7 / 2 and 5 / 2 characteristic peaks of Bi 4f in Zn@BiSb shift towards lower binding energies; similarly, compared with Zn@Sb, the 3 / 2 and 5 / 2 characteristic peaks of Sb 3d in Zn@BiSb shift towards lower binding energies; meanwhile, the 1 / 2 and 3 / 2 characteristic peaks of Zn 2p in Zn@BiSb shift towards higher binding energies compared to Bare Zn, Zn@Bi, and Zn@Sb. Figure 1 (d) indicates that compared with Bi and Sb monometals, the co-introduction of Bi and Sb bimetals results in a stronger electron transfer with Zn, which helps to form metallic bonds between Bi, Sb and metallic Zn, thereby enhancing the bonding force between Bi and Zn and Sn and Zn. This is beneficial to enhancing the stability of the BiSb bimetallic layer during long-term cycling.

[0032] Example 9 The electrode-assembled symmetrical cells prepared in Examples 1-5 at different replacement durations were used at 1 mA cm⁻¹. -2 0.5mAh cm -2 A constant current charge-discharge test was then performed. Figure 2As shown, both excessively short and excessively long reaction times are detrimental to Zn deposition / stripping behavior. At reaction times of 1 min and 10 min, the cells failed within approximately 250 h. At 3 min, nearly 1200 h of cycling performance was achieved, but electrode polarization gradually increased with increasing cycle time. This indicates that the electrode surface layer cannot regulate Zn deposition / stripping behavior with increasing cycle time, ultimately leading to a short circuit. Cycle times exceeding 1800 h were achieved at reaction times of 5 min and 7 min, but severe voltage fluctuations occurred during the initial 7 min cycle, indicating that Zn deposition / stripping behavior is affected during cycling. 2+ The deposition behavior was affected, possibly due to an excessively long reaction time and an overly thick BiSb bimetallic layer on the surface hindering the deposition of Zn. 2+ The deposition process was efficient, and a reaction time of 5 min resulted in stable voltage during deposition, with a cycle time exceeding 1800 h. Therefore, the sample with a displacement reaction time of 5 min was selected as the optimal sample, denoted as the Zn@BiSb electrode.

[0033] Example 10 Symmetrical cells were assembled using Zn@BiSb, Zn@Bi, Zn@Sb, and Bare Zn zinc electrodes prepared in Examples 1, 6, 7, and Comparative Example 1, and then subjected to constant current charge-discharge tests. Figure 3 As shown, the cycling times of Bare Zn, Zn@Bi, and Zn@Sb all did not exceed 400 h, which may be related to the non-uniform morphology of the electrode surface, resulting in Zn... 2+ The uneven deposition of the zinc electrode led to dendrite growth, ultimately causing a short circuit. Comparing the overpotentials of Zn@BiSb, Zn@Bi, Zn@Sb, and Bare Zn electrodes, the results showed that the overpotential of the Zn@BiSb electrode was lower than that of the other electrodes. This indicates that the BiSb bimetallic layer is beneficial for reducing electrode polarization and promoting Zn deposition. 2+ Deposition / stripping process.

[0034] Example 11 The Zn@BiSb and Bare Zn zinc electrodes prepared in Example 1 and Comparative Example 1 were used to analyze the effect of the BiSb bimetallic layer on Zn. 2+ The positive effects of deposition / stripping behavior were investigated by fitting the exchange current density of Zn@BiSb and Bare Zn electrodes under different current densities using overpotential fitting. Figure 4 a). The results show that the exchange current density of Bare Zn is 6.85 mAcm⁻¹. -2 The exchange current density of Zn@BiSb is 14.33 mA cm⁻¹. -2The high exchange current density indicates a rapid electron transfer kinetic process on the Zn@BiSb surface, which is beneficial for promoting the reaction kinetics of Zn. CA tests were performed at a potential of 150 mV. Figure 4 b). The results show that during the 600 s deposition process, Zn 2+ 2D diffusion occurs continuously on the surface of the Bare Zn electrode because Zn undergoes deposition during the deposition process. 2+ Uneven deposition continues, which in severe cases can lead to the growth of Zn dendrites, piercing the diaphragm and ultimately causing a short circuit; while Zn 2+ After a short period of 2D diffusion, long-term 3D diffusion was achieved on the Zn@BiSb electrode surface, indicating that the BiSb bimetallic layer can modulate Zn diffusion. 2+ The depositional behavior of Zn promotes 2+ Uniform deposition.

[0035] Example 12 AC impedance spectroscopy was performed on Zn@BiSb, Zn@Bi, Zn@Sb, and Bare Zn electrodes prepared in Examples 1, 6, 7, and Comparative Example 1 to further investigate the mechanism of BiSb bimetallic layer-induced uniform Zn deposition. Figure 5 As shown in figure a, the Zn@Bi electrode exhibits the largest Rct, which may be due to the formation of a dense surface layer of Bi metal on the Zn surface, hindering charge transfer. Meanwhile, the Zn@BiSb electrode achieves the smallest charge transfer impedance, indicating that the BiSb bimetallic layer is beneficial for accelerating Zn transfer. 2+ The rapid transfer dynamics process. For example... Figure 5 As shown in b, the half-cell CV curves of each electrode were compared. The results show that the Zn@BiSb electrode obtained the largest oxidation peak current intensity and the largest peak area, indicating that there are abundant nucleation sites on the surface of the Zn@BiSb electrode, which promotes the oxidation of Zn. 2+The Zn@Bi electrode exhibits a faster reaction kinetics than the Bare Zn electrode; however, the oxidation peak intensity is lower on the Zn@Bi electrode compared to the Bare Zn electrode, possibly due to the dense Bi metal layer hindering the Zn reaction. While the Zn@Sb electrode shows better oxidation peak intensity than the Bare Zn electrode, the oxidation peak position is shifted to the right compared to other electrodes, indicating that the Zn@Sb electrode surface weakens the Zn reactivity. Furthermore, the Zn@BiSb electrode exhibits the smallest redox electrode polarization (-0.045 / -0.006 V) compared to other electrodes, while the redox electrode polarizations for Bare Zn, Zn@Bi, and Zn@Sb electrodes are -0.116 / 0.015 V, -0.092 / 0.011 V, and -0.053 / -0.001 V, respectively. In summary, the Zn@BiSb electrode promotes the thermodynamics of Zn deposition / exfoliation reactions and provides abundant nucleation sites, accelerating the fast reaction kinetics of Zn. Figure 5 As shown in Figure c, the nucleation overpotentials of each electrode were tested at a current of 1 mA. The results show that the nucleation overpotentials of Bare Zn, Zn@Sb, Zn@Bi, and Zn@BiSb are 88.3, ​​53.8, 64.8, and 44.6 mV, respectively. Among them, Zn@BiSb obtained the lowest nucleation overpotential, indicating that the BiSb bimetallic layer can effectively reduce the nucleation energy barrier compared to the single metal layer, promoting Zn nucleation. 2+ The deposition process of Zn. In summary, compared with monometallic protective layers and pure Zn interface layers, BiSb bimetallic layers provide abundant nucleation sites, promoting Zn deposition. 2+ Uniform deposition was achieved; and the best Zn was obtained. 2+ The rapid transfer kinetics and rapid reaction kinetics of Zn accelerate the reaction of Zn and Zn. 2+ The transfer of Zn regulates its deposition / stripping behavior.

[0036] Example 13 Contact angle tests were performed on the Zn@BiSb, Zn@Bi, Zn@Sb, and Bare Zn electrodes prepared in Examples 1, 6, 7, and Comparative Example 1. Figure 6 As shown, the results indicate that the contact angle of the Bare Zn surface is 90.79 degrees. This large contact angle is detrimental to the contact between the solution and the Zn surface, which slows down the Zn... 2+ Electrochemical kinetics at the electrode interface were studied, and Zn@Bi, Zn@Sb, and Zn@BiSb electrodes exhibited good hydrophilicity. Among them, Zn@BiSb achieved the smallest contact angle of 12.95 degrees, which promotes sufficient contact between the solution and the Zn surface and accelerates Zn electrochemical reaction. 2+ The transfer kinetics process; however, full contact between the hydrophilic interface and the Zn surface may increase the risk of electrochemical corrosion.

[0037] Example 14 The Zn@BiSb and Bare Zn electrodes prepared in Example 1 and Comparative Example 1 were subjected to in-situ optical testing and analysis to further visualize the effect of the BiSb bimetallic layer on Zn. 2+ The regulation of deposition behavior was investigated using in-situ optical microscopy to observe in-situ Zn nucleation and growth during Zn deposition on Bare Zn and Zn@BiSb electrodes. Figure 7 As shown, after 20 minutes of deposition, uneven dendrite growth has already formed on the surface of the Bare Zn electrode. This is because, in the early stages of deposition, the Bare Zn surface lacks nucleation sites and is also affected by the "tip effect," causing Zn... 2+ Zn accumulates at protrusions with high electric field strength, and during deposition, 2+ Due to the slow transfer kinetics, Zn deposits before it can diffuse to other areas. This deposition process continues in this manner, eventually forming Zn dendrites. As expected, after 20 minutes, this uneven Zn deposition accelerates dendrite growth, and by 60 minutes, severe dendrite growth is observed on the Bare Zn electrode surface. Conversely, the Zn@BiSb electrode shows no significant dendrite growth during the 0-60 minute deposition process, achieving uniform Zn deposition. This is because the BiSb bimetallic layer provides abundant nucleation sites on the Zn electrode surface, reducing local current density, and possesses good hydrophilicity, which is beneficial for Zn formation. 2+ The rapid transfer and reaction kinetics on the Zn electrode surface ultimately promote the uniform deposition of Zn.

[0038] Example 15 The Zn@BiSb and Bare Zn electrodes prepared in Example 1 and Comparative Example 1 were subjected to long-term full-cell cycling tests. Figure 8 As shown, the capacity retention and coulombic efficiency of the Bare Zn electrode were 58.23% and 99.20%, respectively, while the Zn@BiSb electrode achieved even better capacity retention and coulombic efficiency, at 91.62% and 99.57%, respectively, and yielded a capacity of 213.4 mAh g⁻¹. -1 The initial capacity and 195.2 mAh g -1 The average capacity of the Zn@BiSb electrode is superior to that of the Bare Zn battery. Therefore, using the Zn@BiSb electrode can greatly improve the capacity and cycle stability of the full cell.

[0039] In summary, this invention successfully introduces BiSb bimetals onto the Zn foil surface via a double substitution reaction, thereby accelerating the Zn reaction kinetics, providing abundant nucleation sites, increasing the hydrophilicity of the Zn surface, and promoting the rapid Zn transfer kinetics, thus modulating the Zn reaction. 2+ The deposition behavior of Zn promotes uniform Zn growth, improving the cycling performance and stability of both symmetric and full cells. Specifically, the symmetric cell assembled with Zn@BiSb electrodes achieves cycling performance at 1 mA cm⁻¹. -2 0.5 mAh cm -2 The full cell assembled with Zn@BiSb electrode and CNT-MnO2 cathode achieved a cycling performance of over 1800 h, with a coulombic efficiency of 99.57%, a capacity retention of 91.62%, and a capacity of 213.4 mAh g⁻¹. -1 The initial capacity. These advantages are due to the BiSb bimetallic layer improving the Zn metal surface. 2+ The electrochemical kinetics of the process are described. In summary, this work provides a simple and efficient strategy for introducing bimetals into the surface of Zn foil to improve the electrochemical performance of its electrodes.

[0040] Comparative Example 2 Based on Example 1, only the replacement solution in step (2) is changed from antimony trichloride to antimony oxide, and everything else is the same as in Example 1.

[0041] Comparative Example 3 Based on Example 1, only the replacement solution in step (2) is changed to antimony trichloride or elemental antimony, and everything else is the same as in Example 1. Comparative Example 4 Based on Example 1, only the replacement solution in step (2) is changed from bismuth trichloride to bismuth oxide, and everything else is the same as in Example 1. Comparative Example 5 Based on Example 1, only the replacement solution in step (2) is changed to bismuth trichloride or elemental bismuth, and everything else is the same as in Example 1.

[0042] Table 1. Solubility and symmetric cell life of materials in Example 1 and Comparative Examples 2-5

[0043] We compared material solubility and symmetric cell lifetime (test conditions: current density 1 mA cm⁻¹). -2 0.5mAh capacity -2 ), specific data are shown in Table 1.

[0044] In Example 1, when the raw materials were completely dissolved, the symmetric cell lifetime was significantly extended (1800 h, far exceeding the 310 h, 420 h, 460 h, and 400 h of Comparative Examples 2-5). The high solubility of BiCl3 and SbCl3 in ethanol used in Example 1 ensured the high efficiency and uniformity of the substitution reaction, resulting in a dense, stable BiSb bimetallic coating with excellent zinc affinity. This coating not only provides abundant nucleation sites but also reduces Zn... 2+ The nucleation overpotential significantly enhances the interfacial kinetic stability of the Zn electrode. Conversely, the oxides or elemental metals used in Comparative Examples 2–5 suffer from insufficient solubility, leading to incomplete substitution reactions, loose coating structures, and poor adhesion. This results in an inability to effectively suppress dendrite growth and side reactions, ultimately causing a significant reduction in battery cycle life. Therefore, this invention, by selecting soluble metal salts as precursors, achieves precise control over the Zn electrode interfacial structure, providing a reliable material basis for its long-term cycling performance in aqueous zinc-ion batteries.

[0045] Furthermore, this invention chooses dichloro salts for preparation primarily because bismuth chloride and antimony chloride are more soluble in chloride-containing environments and form stable complex ions, avoiding the formation of insoluble bismuth hydroxide or basic salts, thus ensuring the presence of free Bi in the solution. 3+ Sb 3+ The concentration is sufficient to allow a displacement reaction with zinc. If other salts (such as sulfates or nitrates) are used, they are prone to hydrolysis, producing precipitates and hindering the reaction from proceeding. Zinc and Bi 3+ Sb 3+ Zn is generated after substitution 2+ Zinc chloride (ZnCl2) is readily soluble in water and will not form a sparingly soluble salt coating on the zinc sheet surface, thus avoiding hindering the reaction between zinc and Bi. 3+ Further contact ensures efficient reaction. The acidic environment of the chloride system can inhibit Bi... 3+ Hydrolysis occurs, and zinc readily loses electrons under acidic conditions (enhancing reducing power), thus promoting the thermodynamic process of the displacement reaction. Other salts cannot simultaneously satisfy the dual requirements of inhibiting hydrolysis and promoting electron transfer. Therefore, the choice of chloride salts is mainly to ensure the stable presence of bismuth ions in solution, avoid byproducts hindering the reaction, and adapt to the reducing conditions of zinc, thereby efficiently achieving bismuth displacement. Furthermore, the coating morphology and thickness can be precisely controlled by adjusting the concentration and time.

[0046] This indicates that the technical solution of the present invention achieves optimization of the solubility of electrode materials through specific design, which greatly improves the cycle stability and lifespan of zinc-ion batteries, and has technological advancement and patent protection value.

[0047] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in these embodiments can be arbitrarily combined without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for preparing a BiSb bimetallic coated zinc electrode material, characterized in that: The method includes the following steps: (1) Cleaning of negative electrode material: The zinc negative electrode material is ultrasonically cleaned in an organic solvent; (2) Preparation of the replacement solution: BiCl3 and SbCl3 were added to the organic solution and stirred to obtain the replacement solution; (3) The zinc negative electrode material obtained in step (1) is used as the working electrode and placed in the displacement solution obtained in step (2) for a period of time to obtain the modified zinc electrode material.

2. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 1, characterized in that: The organic solvent in step (1) is anhydrous ethanol, with a mass percentage of 75-99.5%, preferably 99.5% anhydrous ethanol.

3. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 1, characterized in that: In step (2), the organic solvent is anhydrous ethanol, and the solid-liquid ratio of BiCl3, SbCl3 and anhydrous ethanol is (0.05-0.15):(0.15-0.25):(110-130) (g / g / mL).

4. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 3, characterized in that: The organic solvent in step (2) is anhydrous ethanol, and the solid-liquid ratio of BiCl3, SbCl3 and anhydrous ethanol is 0.100:0.200:120 (g / g / mL).

5. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 1, characterized in that: The stirring conditions in step (2) are 20-30℃ and the stirring time is 10-14 hours.

6. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 5, characterized in that: The stirring conditions were: temperature 25℃, stirring time 12 hours.

7. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 1, characterized in that: In step (3), one side of the zinc negative electrode material is covered with anti-organic tape to achieve a one-sided reaction of zinc.

8. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 1, characterized in that: In step (3), the zinc anode material is placed in the replacement solution for 1-10 minutes to react.

9. The method for preparing the BiSb bimetallic coated zinc electrode material according to claim 8, characterized in that: The replacement time is 1 min, 3 min, 5 min, 7 min or 10 min.

10. The aqueous zinc-ion battery material obtained by the method for preparing the BiSb bimetallic coated zinc electrode material according to any one of claims 1-9 is used as the negative electrode material in an aqueous zinc-ion battery.

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