Self-healing zinc powder integrated negative electrode material and preparation method thereof

Abstract

The invention discloses a self-healing zinc powder integrated negative electrode material and a preparation method thereof, the chemical composition expression of the material is Zn-xM-yP-zN, in the formula, x, y and z are respectively mass percentages of M, P and N, x is more than or equal to 5 and less than or equal to 15, y + z is more than or equal to 5 and less than or equal to 15, y is more than or equal to z, and the balance is Zn, M is an MBenes material, P is protein, and N is N-carboxyl anhydride; the material is obtained by mixing zinc powder subjected to acid treatment with a protein solution to prepare amyloid fiber composite zinc powder, then adding the amyloid fiber composite zinc powder into an MBenes solution, performing ultrasonic stirring, then dropwise adding an N-carboxyl anhydride solution containing a quaternary ammonium carboxylate initiator, and performing secondary ultrasonic stirring. The preparation method is simple, the process is easy to control, and the prepared material has the characteristics of self-healing, high mechanical strength, strong binding force, excellent cycling stability and the like, and can be widely applied to the fields of wearable equipment, electric automobiles and the like.

Description

Technical Field

[0001] This invention belongs to the field of battery materials and relates to a self-healing zinc powder integrated negative electrode material and its preparation method. Background Technology

[0002] Aqueous zinc-ion batteries have become a research hotspot in the energy storage field due to their good safety, low cost, and high energy density. Zinc is abundant and has a high specific capacity (820 mAh·g). -1 Zinc exhibits good stability in aqueous environments, and its suitable redox potential (-0.76 V vs. SHE) in aqueous electrolytes makes it an ideal anode material for aqueous batteries. Currently, zinc anodes are divided into zinc foil anodes and zinc powder anodes. Unlike the widely used zinc foil anode, zinc powder anodes have a larger specific surface area and higher processability. However, in aqueous electrolytes, zinc powder undergoes dendrite growth, corrosion passivation, and hydrogen evolution side reactions. Furthermore, the volume of zinc powder anodes changes significantly during battery cycling, which is detrimental to the interfacial stability of zinc powder particles and battery performance. Simultaneously, zinc powder anodes inevitably develop defects during cycling, and the exacerbation of these defects can lead to electrode failure, limiting the rate performance and long-term stability of zinc powder anodes. To address these issues, the key lies in designing composite zinc powder anodes with high conductivity, high structural stability, and self-healing capabilities.

[0003] Protein amyloid fibers are protein self-assemblies exhibiting a highly ordered nanoscale fibrous structure. They contain amino and carboxyl groups that can bind to zinc ions. To enhance their structural stability, they can be compounded with other polymers and used to inhibit and repair damage to the zinc powder anode interface layer. MXenes are ternary layered carbides / nitrides with good conductivity, tunable surface structure, and abundant functional groups, while also possessing certain mechanical strength. MBenes, a ternary layered transition metal boride, combines the advantages of MXenes with stronger oxidation resistance, higher Young's modulus, and more diverse structures. These two types of ternary layered compounds are ideal materials for modifying the zinc anode interface. Combining zinc powder, protein amyloid fibers, and MBenes yields composite zinc powder anodes with good conductivity and stable electrode interfaces and morphology. However, current technologies for modifying zinc powder anodes based on protein materials or ternary layered compounds are still immature. Existing patents and research findings on zinc powder anode modification schemes generally have many shortcomings, specifically: The sulfonated silk protein gel-modified aqueous zinc electrode scheme disclosed in Chinese invention patent application No. 202510260461.0, while improving cycling performance, suffers from low zinc utilization due to the zinc electrode sheet as the substrate. Furthermore, the chlorosulfonic acid and pyridine used have poor safety and environmental friendliness, and the preparation process is cumbersome. The zinc powder anode prepared by coating zinc powder with silicon / fluorine group resin in Chinese invention patent application No. 202510278455.8, while possessing certain mechanical strength, suffers from insufficient contact between the resin and zinc powder, requiring the addition of conductive agents and binders. Moreover, the zinc powder easily separates from the resin during cycling, resulting in poor performance. (Journal of Colloid and Interface) The MXene-coated zinc powder anode reported in *Science*, 680(A), pp. 657-664, exhibits conductivity and resistance to deformation. However, the MXene layer is prone to distortion and loss during cycling and cannot self-heal. (0.2 A·g) -1 After 515 cycles at the current density, the capacity retention dropped to 77.4%. In summary, the current drawbacks of zinc powder anodes include: First, zinc powder, conductive agents, and binders are often prepared by mechanical grinding, which is a complicated process and results in poor bonding between them, making it impossible to achieve stable cycle performance under long-term high-rate use conditions. Second, it cannot perform dynamic self-repair when subjected to certain external forces or damage; Third, the safety and environmental friendliness of the raw materials used are difficult to ensure, and the process is relatively complex, making it unsuitable for large-scale production. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention aims to provide a self-healing zinc powder integrated anode material and its preparation method. The chemical composition of this material is Zn-xM-yP-zN, where x, y, and z are the mass percentages of M, P, and N, respectively, with 5≤x≤15, 5≤y+z≤15, and y≥z, and the balance being Zn. M represents MBenes material, P represents protein, and N represents N-carboxylic acid anhydride. This material is prepared by mixing acid-treated zinc powder with a protein solution to obtain starch-like fiber composite zinc powder, which is then added to an MBenes solution and ultrasonically stirred. Next, an N-carboxylic acid anhydride solution containing a quaternary ammonium carboxylate initiator is added dropwise, followed by a second ultrasonic stirring. The preparation method of this invention is simple and the process is easy to control. The resulting material exhibits self-healing properties, high mechanical strength, strong bonding force, and excellent cycle stability, and can be widely used in wearable devices and electric vehicles.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A self-healing zinc powder integrated negative electrode material has the chemical composition formula Zn-xM-yP-zN, where x, y, and z are the mass percentages of M, P, and N, respectively, 5≤x≤15, 5≤y+z≤15 and y≥z, and the balance is Zn; M is MBenes material, P is protein, and N is N-carboxylic acid anhydride.

[0006] As a limitation of the present invention, the MBenes material is Mo. 4 / 3 One or more of B2, Cr2B2, and V2B2; the protein is one or more of β-lactoglobulin, egg white lysozyme, and soy protein isolate; the N-carboxylic acid anhydride is one or more of L-serine-N-carboxy-cyclic anhydride, L-aspartic acid-N-carboxy-cyclic anhydride, and L-glutamic acid-N-carboxy-cyclic anhydride.

[0007] This invention also provides a method for preparing a self-healing zinc powder integrated negative electrode material, which is carried out in the following order: S1. Soak zinc powder in dilute hydrochloric acid with a concentration of 0.1~2 mol / L for 5~20 min, and after centrifugation and freeze drying, obtain acid-treated zinc powder; S2. After the acid-treated zinc powder is mixed evenly in a protein solution with a mass fraction of 0.25~0.75 wt.%, the pH is adjusted to 2~4.5 with HCl and magnetically stirred. Then, it is centrifuged and freeze-dried to obtain amyloid fiber composite zinc powder. S3. Place the starch-like fiber composite zinc powder in a 10-20 mg / mL MBenes solution and ultrasonically stir for 20-40 min. After ultrasonication, slowly drop it into N-carboxylic acid anhydride containing quaternary ammonium carboxylate initiator at a rate of 50-150 mL / min. Stir magnetically at 40-80℃ for 4-6 h. Then pour it into a polytetrafluoroethylene mold, cool it and take it out to obtain a 0.05-10 mm self-healing zinc powder integrated negative electrode material.

[0008] In this invention, the rate at which the mixed solution of amyloid fiber composite zinc powder and MBENS solution is added dropwise into the N-carboxylic acid anhydride solution containing a quaternary ammonium carboxylate initiator affects the polymerization process. If the addition is too fast, the local concentration of N-carboxylic acid anhydride will be too high, resulting in uneven distribution of N-carboxylic acid anhydride; if the addition is too slow, the reaction rate will be too slow, resulting in insufficient reaction conversion.

[0009] As a limitation of the preparation method of the present invention, in step S1, the centrifugation speed is 3000~6000 rpm and the time is 10~30 min.

[0010] As another limitation of the preparation method of the present invention, in step S1, the temperature during freeze drying is -80℃ to -40℃, and the time is 24 to 48 h.

[0011] As a third limitation of the preparation method of the present invention, in step S2, the temperature during magnetic stirring is 40~90℃ and the time is 30~120 min.

[0012] As a fourth limitation of the preparation method of the present invention, in step S2, the centrifugation speed is 3000~6000 rpm and the time is 10~30 min.

[0013] As a fifth limitation of the preparation method of the present invention, in step S2, the temperature during freeze drying is -80℃ to -40℃, and the time is 24 to 48 h.

[0014] In this invention, the temperature and time during freeze-drying affect the integrity of the product structure. At this temperature and time, uniform ice crystal sublimation occurs, resulting in an ordered and complete internal porous structure. If the temperature is below this, irreversible phase separation or crystallization will occur, destroying the uniformity of the product's microstructure. If the temperature is above this, uneven freezing will occur, leading to a temperature gradient inside the product and further inducing internal stress damage.

[0015] As a sixth limitation of the preparation method of the present invention, in step S3, the N-carboxylic acid anhydride solution containing quaternary ammonium carboxylate initiator is an aqueous solution of N-carboxylic acid anhydride with a concentration of 2.5~7.5 mg / mL containing tetramethylacetate; the preparation process is as follows: dissolve 0.1~0.5 g of tetramethylacetate and 0.25~0.75 g of N-carboxylic acid anhydride in 100 mL of deionized water and stir for 20~40 min.

[0016] This invention modifies zinc powder anodes using MBEnes, proteins, and N-carboxylic anhydrides. These three components form a tightly coupled functional system through multi-level interactions, collectively endowing the electrode with excellent overall performance. Specifically, proteins and N-carboxylic anhydrides form a dynamic three-dimensional network through amino / carboxyl crosslinking, and are tightly bound to MBEnes via electrostatic interactions, jointly constructing a stable conductive composite framework. MBEnes provide a rigid supporting framework and efficient conductive pathways for the three-dimensional network, while the three-dimensional crosslinked network provides a uniformly dispersed carrier for the MBEnes. The two are coupled together to form a composite substrate that combines structural stability and high conductivity.

[0017] In this composite system, the interactions of the components form a functional coupling: the conductive network constructed by MBENS ensures rapid charge transport, providing Zn... 2+ The migration and coordination processes provide kinetic support; the proteins and N-carboxylic anhydrides in the three-dimensional cross-linked network provide abundant carboxyl and amino coordination sites. The two work together to facilitate the dissolution of zinc powder during charging and discharging, thereby generating Zn. 2+ It can reversibly bind to coordination sites, thereby achieving dynamic and efficient repair of electrode microcracks and defects.

[0018] The combined effect of the aforementioned multi-level interactions and functional coupling cannot be achieved by a single component independently, but is the result of mutual support and functional complementarity among the components. This system effectively overcomes the technical bottleneck that single modification methods cannot simultaneously achieve electrode structural stability, conductivity, and long-term cycle repair capability, significantly enhancing the structural integrity and electrochemical interface stability of the electrode, and ultimately greatly extending the long-term cycle life of the zinc powder anode.

[0019] The above-mentioned technical solution of the present invention is a whole in which each step is closely related and mutually influential, and together they determine the morphological characteristics and performance of the product.

[0020] The above technical solution has the following advantages or beneficial effects: 1. The zinc powder integrated negative electrode material prepared by this invention has good self-healing ability. The protein surface group is rich and can coordinate with zinc ions generated by damage and corrosion, which not only enhances the protein-metal bonding, but also generates a composite coating to achieve self-healing. 2. In this invention, the N-carboxylic acid anhydride undergoes a cross-linking reaction with the surface groups of the protein, and the N-carboxylic acid anhydride monomer polymerizes. The binding force within the system is strong, which can adapt to long-term, high-rate battery cycle operation. 3. The raw materials used in this invention are mild and mainly biomass raw materials, resulting in a highly environmentally friendly product; 4. The preparation method of this invention is simple, the process is easy to control, and it is suitable for large-scale industrial production.

[0021] This invention is applicable to the preparation of self-healing zinc powder integrated anode materials.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0023] Figure 1 This is a scanning electron microscope image of zinc powder after acid treatment in Example 1 of the present invention; Figure 2 This is a cross-sectional scanning electron microscope image of the self-healing zinc powder integrated negative electrode material prepared in Example 1 of the present invention; Figure 3 The stress-strain curves of the zinc powder anode materials prepared in Example 1 and Comparative Example 1 of this invention are shown. Figure 4 The voltage cycle time curves are shown for symmetrical batteries assembled in 2 M ZnSO4 electrolyte using zinc powder anode materials prepared in Example 1 and Comparative Examples 1-2 of the present invention. Figure 5 The graph shows the relationship between the coulombic efficiency and the number of cycles of the zinc / copper asymmetric battery assembled in 2 M ZnSO4 electrolyte using the self-healing integrated zinc powder anode material prepared in Examples 1-3 of this invention. Figure 6 The images shown are self-healing test diagrams of the self-healing zinc powder integrated negative electrode material prepared in Example 2 of the present invention, wherein: (a) is the initial sample image, (b) is the sample image after 1 cycle, and (c) is the sample image after 5 cycles. Figure 7 This is a scanning electron microscope (SEM) image of the self-healing zinc powder integrated negative electrode material prepared in Example 3 of the present invention. Figure 8 The voltage cycle time curves are shown for the zinc powder anode materials prepared in Comparative Examples 3-5 of this invention, when assembled into symmetrical coin cells in 2 M ZnSO4 electrolyte. Detailed Implementation

[0024] The following embodiments are merely some, not all, of the embodiments of the present invention. Therefore, the detailed descriptions of the embodiments provided below are not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0026] Example 1 This embodiment prepares a self-healing zinc powder integrated anode material, and the preparation process and steps are as follows: S1. Soak 7 g of zinc powder in 1 mol / L dilute hydrochloric acid for 10 min, centrifuge at 3000 rpm for 30 min, and freeze dry at -40℃ for 48 h to obtain acid-treated zinc powder. S2. The acid-treated zinc powder was placed in a 0.75 wt.% β-lactoglobulin solution (the preparation method of 0.75 wt.% β-lactoglobulin solution: mix 0.75 g of β-lactoglobulin powder with 99.25 g of ultrapure water and stir for 5 min). After mixing evenly, the pH was adjusted to 3 with HCl, and the mixture was magnetically stirred at 60℃ for 60 min. Then, it was centrifuged at 3000 rpm for 30 min and freeze-dried at -40℃ for 48 h to obtain amyloid fiber composite zinc powder. S3, Place the amyloid fibrous zinc powder in a solution with a concentration of 15 mg / mL Mo 4 / 3 B2 solution (15 mg / mL Mo) 4 / 3 Preparation method of B2 solution: Take 1.5 g of Mo 4 / 3 B2 was mixed with 100 mL of deionized water and stirred for 5 min. The mixture was then ultrasonically stirred for 30 min. After ultrasonication, it was slowly added dropwise at a rate of 150 mL / min to an aqueous solution of 7.5 mg / mL L-serine-N-carboxy-cyclic anhydride containing tetramethylacetate (the preparation method of the aqueous solution of 7.5 mg / mL L-serine-N-carboxy-cyclic anhydride containing tetramethylacetate is as follows: take 0.3 g of tetramethylacetate, 0.75 g of L-serine-N-carboxy-cyclic anhydride and 100 mL of deionized water and stir for 20 min). The mixture was then magnetically stirred at 60 °C for 5 h. The mixture was then poured into a polytetrafluoroethylene mold, cooled, and removed to obtain a 0.05 mm self-healing zinc powder integrated negative electrode material.

[0027] Example 2 This embodiment prepares a self-healing zinc powder integrated anode material, and the preparation process and steps are as follows: S1. 7.5 g of zinc powder was soaked in 0.1 mol / L dilute hydrochloric acid for 20 min, centrifuged at 4500 rpm for 20 min, and then freeze-dried at -60℃ for 32 h to obtain acid-treated zinc powder. S2. The acid-treated zinc powder was placed in a 0.7 wt.% egg white lysozyme solution (the preparation method of 0.7 wt.% egg white lysozyme solution: take 0.7 g of egg white lysozyme powder and add it to 99.3 g of ultrapure water and stir for 5 min). After mixing evenly, the pH was adjusted to 2 with HCl, and the mixture was magnetically stirred at 40℃ for 120 min. Then, it was centrifuged at 4500 rpm for 20 min and freeze-dried at -60℃ for 32 h to obtain amyloid fiber composite zinc powder. S3. Place the starch-like fiber composite zinc powder in a 20 mg / mL Cr2B2 solution (preparation method of 20 mg / mL Cr2B2 solution: mix 1.25 g Cr2B2 with 62.5 mL deionized water and stir for 5 min) and sonicate for 20 min. After sonication, slowly add it dropwise at a rate of 50 mL / min to a 5.5 mg / mL aqueous solution of L-aspartic acid-N-carboxy-cyclic anhydride containing tetramethylacetate (preparation method of 5.5 mg / mL aqueous solution of L-aspartic acid-N-carboxy-cyclic anhydride containing tetramethylacetate: mix 0.5 g tetramethylacetate, 0.55 g L-aspartic acid-N-carboxy-cyclic anhydride with 100 mL deionized water and stir for 30 min). Stir magnetically at 80℃ for 4 h, then pour it into a polytetrafluoroethylene mold, cool it and remove it to obtain a 1 mm self-healing zinc powder integrated negative electrode material.

[0028] Example 3 This embodiment prepares a self-healing zinc powder integrated anode material, and the preparation process and steps are as follows: S1. Soak 9 g of zinc powder in 2 mol / L dilute hydrochloric acid for 5 min, centrifuge at 6000 rpm for 10 min, and freeze dry at -80℃ for 24 h to obtain acid-treated zinc powder. S2. The acid-treated zinc powder was placed in a 0.25 wt.% soy protein isolate solution (the preparation method of 0.25 wt.% soy protein isolate solution: mix 0.25 g of soy protein isolate powder with 99.75 g of ultrapure water and stir for 5 min). After mixing evenly, the pH was adjusted to 4.5 with HCl, and the mixture was magnetically stirred at 90℃ for 30 min. Then, it was centrifuged at 6000 rpm for 10 min and freeze-dried at -80℃ for 24 h to obtain starch-like fiber composite zinc powder. S3. Place the starch-like fiber composite zinc powder in a 10 mg / mL V2B2 solution (preparation method of 10 mg / mL V2B2 solution: mix 0.5 g V2B2 with 50 mL deionized water and stir for 5 min) and sonicate for 40 min. After sonication, slowly add it dropwise at a rate of 100 mL / min to a 2.5 mg / mL aqueous solution of L-glutamic acid-N-carboxy-cyclic anhydride containing tetramethylacetate (preparation method of 2.5 mg / mL aqueous solution of L-glutamic acid-N-carboxy-cyclic anhydride containing tetramethylacetate: mix 0.1 g tetramethylacetate, 0.25 g L-glutamic acid-N-carboxy-cyclic anhydride with 100 mL deionized water and stir for 40 min). Stir magnetically at 40℃ for 6 h, then pour it into a polytetrafluoroethylene mold, cool it and remove it to obtain a 10 mm self-healing zinc powder integrated negative electrode material.

[0029] Comparative Example To investigate the influence of different raw materials on the performance of the product during the preparation process of this invention, the following comparative experiments were conducted. Different zinc powder anode materials were prepared according to the following comparative examples: Comparative Example 1 This comparative example prepares a zinc powder anode material. The preparation process is similar to that of Example 1, except that Mo is not added in step S3. 4 / 3 B2, that is: after obtaining the amyloid fiber composite zinc powder, it is directly added to 7.5 mg / mL of an aqueous solution of L-serine-N-carboxyl-cyclic anhydride containing tetramethylacetate.

[0030] Comparative Example 2 This comparative example prepares a zinc powder anode material. The preparation process is similar to that of Example 1, except that step S2 is omitted, i.e., the acid-treated zinc powder is directly placed in a 15 mg / mL Mo solution. 4 / 3 The solution was ultrasonically stirred and then added dropwise to a 7.5 mg / mL aqueous solution of L-serine-N-carboxylic acid anhydride containing tetramethylacetate. The remaining reaction parameters were the same as in Example 1.

[0031] Comparative Example 3 This comparative example prepares a zinc powder anode material. The preparation process is similar to that of Example 1, except that in step S3, an aqueous solution of L-serine-N-carboxyl-cyclic anhydride containing tetramethylammonium acetate is not added. That is, the starch-like fiber composite zinc powder is placed in a solution with a concentration of 15 mg / mL Mo 4 / 3 After ultrasonic stirring, the B2 solution was poured directly into a polytetrafluoroethylene mold and cooled.

[0032] Comparative Example 4 This comparative example prepares a zinc powder anode material by combining acid-treated zinc powder with β-lactoglobulin and Mo. 4 / 3 B2 and L-serine-N-carboxy-cyclic anhydride were placed together in a ball mill and ball-milled for 3 hours.

[0033] Comparative Example 5 This comparative example prepares a zinc powder anode material. The preparation process is similar to that of Example 1, except that in step S2, β-lactoglobulin is replaced with type I collagen.

[0034] Performance testing The zinc powder anode materials prepared in Examples 1-3 and Comparative Examples 1-5 of this invention were subjected to a series of tests, and the test results are as follows: like Figure 1 The image shows a scanning electron microscope (SEM) image of zinc powder after acid treatment according to Example 1 of this invention. It can be observed that after acid treatment, the zinc powder particles have a particle size distribution of approximately 5 µm, an approximately spherical morphology, and exhibit good dispersibility. The particle surface shows a significantly rough texture, which is caused by micro-area corrosion from the acid solution.

[0035] like Figure 2 The image shown is a cross-sectional scanning electron microscope (SEM) image of the self-healing zinc powder integrated negative electrode material prepared in Example 1 of this invention. Analysis of the image reveals that the thickness of the self-healing zinc powder integrated negative electrode is approximately 50 µm, with good overall thickness uniformity. Furthermore, no obvious pores or structural defects were observed in the cross-sectional area, indicating that the negative electrode material has high density.

[0036] like Figure 3 Figure 1 shows the stress-strain curves of the zinc powder anode materials prepared in Example 1 and Comparative Example 1 of this invention. As can be seen from the figure, the material prepared in Example 1 exhibits a tensile strength of 12.9 MPa and a strain of 24.6%, demonstrating excellent mechanical strength and good toughness. In contrast, the material prepared in Comparative Example 1 has only a tensile strength of 7.2 MPa and a strain of 10.8%, showing significantly worse mechanical strength and toughness compared to Example 1. This is because the absence of MBEnes weakens the bond between the zinc powder anode particles and the N-carboxylic anhydride.

[0037] like Figure 4 The figure shows the voltage-cycle time curves of symmetrical cells assembled in 2 M ZnSO4 electrolyte using zinc powder anode materials prepared in Example 1 and Comparative Examples 1-2 of this invention, with a test condition of current density of 3 mA·cm⁻¹. -2 Surface capacity 3 mAh·cm -2 The test results show that the symmetrical battery assembled using the materials prepared in Example 1 can cycle stably for 800 hours. During the cycle, the voltage curve remains stable, with no significant increase in polarization or short circuit, demonstrating good cycle stability and interface compatibility. In contrast, the symmetrical battery assembled using the materials prepared in Comparative Example 2 experiences a short circuit after 300 hours of cycling, exhibiting poor cycle life. This is because the lack of protein bridging makes its structure loose, ultimately leading to poor cycle life. The symmetrical battery assembled using the materials prepared in Comparative Example 1 can only cycle for 100 hours, with a significant increase in overpotential and extremely unstable cycling. This is because the internal structure lacks MBENS connections, making it prone to structural collapse during cycling, resulting in a reduction in electrode active sites and an increase in overpotential.

[0038] like Figure 5 The figure shows the relationship between the coulombic efficiency and the number of cycles of the self-healing integrated zinc powder anode materials prepared in Examples 1-3 of this invention assembled in a 2 M ZnSO4 electrolyte for zinc / copper asymmetric batteries. As can be seen from the figure, the materials prepared in different examples all exhibit good electrochemical reversibility and cycle stability after being assembled into asymmetric batteries: the average coulombic efficiency of the material in Example 1 is about 99%, and it can be stably cycled for 247 cycles; the average coulombic efficiency of the material in Example 2 is close to 98%, and it can be stably cycled for 163 cycles; the average coulombic efficiency of the material in Example 3 is about 95%, and it can be stably cycled for 115 cycles.

[0039] like Figure 6 The image shows a self-healing test result of the self-healing zinc powder integrated negative electrode material prepared in Example 2 of this invention. The test process was as follows: after creating scratches on the material surface with a blade, it was assembled into a symmetrical aqueous zinc-ion battery. The test results showed that the initial cracks were largely healed after one cycle, and the cracks were almost completely healed after five cycles. This is because the Zn produced during the charging and discharging process... 2+ It can reversibly coordinate with the carboxyl / amino groups in proteins and N-carboxylic anhydride molecules, thereby endowing the material with significant self-healing properties.

[0040] like Figure 7 The image shows a scanning electron microscope (SEM) image of the self-healing zinc powder integrated negative electrode material prepared in Example 3 of this invention. As can be seen from the image, the zinc powder particles in the prepared negative electrode material are uniformly distributed, with a dense surface structure and no obvious pores or aggregation, indicating that the integrated negative electrode has good structural uniformity and densification characteristics.

[0041] like Figure 8 The figure shows the voltage-cycle time curves of the zinc powder anode materials prepared in Comparative Examples 3-5 of this invention assembled into symmetrical coin cells in 2 M ZnSO4 electrolyte. It can be seen from the figure that at 5 mA·cm⁻¹… -2 / 1 mAh·cm -2 Under the test conditions, the symmetrical battery assembled using the material prepared in Comparative Example 3 experienced a short circuit after 6 hours of cycling, indicating poor cycle life. This is because the lack of cross-linking with N-carboxylic acid anhydride resulted in a loose material structure and poor mechanical strength. Furthermore, the volume change of zinc powder particles during cycling caused electrode structure damage, leading to poor cycle life. The symmetrical battery assembled using the material prepared in Comparative Example 4 experienced a short circuit after 27 hours, also indicating poor cycle life. This is because ball milling was insufficient to fully coat the zinc powder particles with protein and N-carboxylic acid anhydride, exposing the zinc powder particles in the electrolyte, leading to the formation of zinc dendrites and causing a short circuit during cycling. The symmetrical battery assembled using the material prepared in Comparative Example 5 experienced a short circuit after 40 hours. This is because ordinary collagen cannot undergo fibrosis and cannot form a through-and-through nanofiber network framework, significantly deteriorating the three-dimensional structure and self-healing ability of the resulting composite material, ultimately resulting in poor cycle life.

[0042] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A self-healing zinc powder integrated negative electrode material, characterized in that, Its chemical composition formula is Zn-xM-yP-zN, where x, y, and z are the mass percentages of M, P, and N, respectively, 5≤x≤15, 5≤y+z≤15 and y≥z, and the balance is Zn; M is MBenes material, P is protein, and N is N-carboxylic anhydride.

2. The self-healing zinc powder integrated negative electrode material according to claim 1, characterized in that, The MBEnes material is Mo 4 / 3 One or more of B2, Cr2B2, and V2B2; the protein is one or more of β-lactoglobulin, egg white lysozyme, and soy protein isolate; the N-carboxylic acid anhydride is one or more of L-serine-N-carboxy-cyclic anhydride, L-aspartic acid-N-carboxy-cyclic anhydride, and L-glutamic acid-N-carboxy-cyclic anhydride.

3. The method for preparing a self-healing zinc powder integrated negative electrode material according to claim 1 or 2, characterized in that, Follow these steps in sequence: S1. Soak zinc powder in dilute hydrochloric acid with a concentration of 0.1~2 mol / L for 5~20 min, and after centrifugation and freeze drying, obtain acid-treated zinc powder; S2. After the acid-treated zinc powder is mixed evenly in a protein solution with a mass fraction of 0.25~0.75 wt.%, the pH is adjusted to 2~4.5 with HCl and magnetically stirred. Then, it is centrifuged and freeze-dried to obtain amyloid fiber composite zinc powder. S3. Place the amyloid fiber composite zinc powder in a 10-20 mg / mL MBenes solution and ultrasonically stir for 20-40 min. After ultrasonication, slowly drop it into an N-carboxylic acid anhydride solution containing a quaternary ammonium carboxylate initiator at a rate of 50-150 mL / min. Stir magnetically at 40-80℃ for 4-6 h. Then pour it into a polytetrafluoroethylene mold, cool it, and remove it to obtain a 0.05-10 mm self-healing zinc powder integrated negative electrode material.

4. The preparation method of a self-healing zinc powder integrated negative electrode material according to claim 3, characterized in that, In step S1, the centrifugation speed is 3000~6000 rpm and the time is 10~30 min.

5. The preparation method of a self-healing zinc powder integrated negative electrode material according to claim 3, characterized in that, In step S1, the freeze-drying temperature is -80℃ to -40℃, and the time is 24 to 48 hours.

6. The preparation method of a self-healing zinc powder integrated negative electrode material according to claim 3, characterized in that, In step S2, the temperature during magnetic stirring is 40~90℃ and the time is 30~120 min.

7. The preparation method of a self-healing zinc powder integrated negative electrode material according to claim 3, characterized in that, In step S2, the centrifugation speed is 3000~6000 rpm and the time is 10~30 min.

8. The preparation method of a self-healing zinc powder integrated negative electrode material according to claim 3, characterized in that, In step S2, the freeze-drying temperature is -80℃ to -40℃, and the time is 24 to 48 hours.

9. The preparation method of a self-healing zinc powder integrated negative electrode material according to claim 3, characterized in that, In step S3, the N-carboxylic acid anhydride solution containing quaternary ammonium carboxylate initiator is an aqueous solution of N-carboxylic acid anhydride with a concentration of 2.5~7.5 mg / mL containing tetramethylacetate; the preparation process is as follows: dissolve 0.1~0.5 g of tetramethylacetate and 0.25~0.75 g of N-carboxylic acid anhydride in 100 mL of deionized water and stir for 20~40 min.

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