Preparation method of battery electrode based on protein modification and metal battery

Abstract

A preparation method of a battery electrode based on protein modification and a metal battery, wherein the preparation method includes: dissolving protein in a buffer solution to prepare precursor A; dissolving a reducing agent in a buffer solution to prepare precursor B; mixing precursor A and precursor B to prepare a mixed solution; covering an electrode substrate on the surface of the mixed solution and incubating at room temperature in an air atmosphere to obtain a protein-modified electrode substrate; taking out, washing, and drying the protein-modified electrode substrate to obtain a protein-modified battery electrode. The present invention realizes uniform lithium ion flux and promotes the lithium ion desolvation process, can achieve uniform lithium atom nucleation, deposition, and growth, effectively inhibits the growth of dendrites, and exhibits excellent electrochemical performance in asymmetric batteries such as Li-Cu, Zn-Ti, Na-Al, K-Al, symmetric batteries such as Li-Li, Zn-Zn, Na-Na, K-K, and all-solid batteries such as Li-LiFePO4, Zn-MnO2, Na-Na3V2(PO4)3, K-K3V2(PO4)3.

Description

Technical Field

[0001] The present invention relates to the field of metal batteries and electrode design, and particularly to a preparation method of a battery electrode based on protein modification and a metal battery. Background Art

[0002] Metal batteries (including lithium, sodium, potassium, magnesium, aluminum, zinc metal batteries, etc.) have received extensive attention due to their high energy density and power density, and are considered the most promising choice for the next-generation energy storage and conversion system. Among them, metallic lithium has an extremely low electrochemical potential (-3.04V VS.RHE), low density (0.534g cm -3 ), and an extremely high theoretical specific capacity (3860mAhg -1 ), making it the optimal choice for battery electrode materials with high energy density and power density. A lithium-sulfur battery with metallic lithium as the negative electrode can achieve an energy density of 650Wh kg -1 , and a lithium-air battery can achieve an energy density of 950Wh kg -1 , much higher than the energy density of lithium-ion batteries (250Wh kg -1 ). However, there are still some key scientific problems restricting the further commercial development of lithium metal batteries that have not been effectively solved. These mainly include: 1. The formation of lithium dendrites. Uneven lithium-ion distribution will cause uneven lithium deposition, forming lithium dendrites that pierce the separator, resulting in battery short circuit and thermal runaway. 2. The huge volume expansion of the lithium negative electrode. Due to the characteristic of the lithium negative electrode without a host material, its volume expansion is infinite. 3. Fragile SEI, dead lithium formation, and electrolyte consumption: ① During repeated charge and discharge cycles, cracks will form in the SEI, eventually leading to a broken SEI. ② During the process of lithium stripping, the volume shrinkage further ruptures the SEI and generates dead lithium; ③ Repeated charge and discharge processes form a porous lithium electrode, and the fresh lithium metal contacts the electrolyte, causing consumption of the lithium negative electrode and the electrolyte, resulting in slow ion transport and ultimately causing low Coulombic efficiency and rapid capacity decay of the lithium metal battery, reducing the reversibility of the lithium metal battery. These problems greatly limit the development of lithium metal batteries. Therefore, it is urgent to suppress the formation of lithium dendrites, reduce the volume expansion of the lithium negative electrode, avoid the formation of fragile SEI and dead lithium, reduce electrolyte consumption, improve the Coulombic efficiency and cycle life of lithium metal batteries, and develop a dendrite-free, safe, and stable cycling lithium metal secondary battery.

[0003] Currently, the solutions for lithium anodes and suppressing lithium dendrite growth in modified secondary lithium metal batteries at home and abroad include: 1. Three-dimensional (3D) electrode matrix. Materials such as copper foam can be used to protect lithium metal anodes. On the one hand, these 3D electrode matrix skeletons can serve as support carriers to reduce the infinite volume expansion of lithium metal anodes; on the other hand, the conductive 3D electrode matrix can enable uniform lithium ion deposition, regulate the electric field, reduce the local current density, thereby achieving the effects of inducing lithium deposition, suppressing lithium dendrites, protecting and stabilizing the lithium anode. 2. Artificial SEI. Covering the lithium surface with a protective layer before battery cycling can achieve the effect of stabilizing SEI. The artificial SEI has high toughness and high Young's modulus, which physically hinders the growth of lithium dendrites. At the same time, it also needs to have high lithium ion conductivity. 3. Electric field and magnetic field regulation. By regulating the magnetic field, a large amount of lithium ion deposition at the convex position is avoided, uniform lithium ion flux and locally dynamically uniform lithium ion deposition are achieved, and then a dendrite-free lithium anode is formed, suppressing the growth of lithium dendrites. 4. Solid-state electrolytes. Solid-state electrolytes include inorganic ceramic electrolytes (inorganic lithium ion transport materials such as sulfides, oxides, nitrides, and phosphides) and solid polymer electrolytes (dispersing lithium salts in polymers such as PEO). Solid-state electrolytes integrate electrolytes and separators, can suppress the growth of lithium dendrites, and greatly improve the safety of the battery. 5. Electrolyte modification. Fluorine-containing electrolyte additives can react with lithium metal to form substances with high ionic conductivity such as LiF, which are distributed in SEI, inducing uniform lithium metal deposition. High-concentration electrolytes can increase the limiting current density, thereby suppressing the formation of lithium dendrites. It helps to form uniform lithium deposition, and even at high current densities, the battery has high Coulombic efficiency. However, the above solutions still have their own limitations: 1. In the 3D electrode matrix solution, the high mass of inactive copper foam and the like lead to a decrease in the energy density of the battery. Whether this method can generate an ion concentration gradient to achieve very uniform ion deposition is still full of challenges. 2. In the artificial SEI solution, the high activity of lithium metal still poses challenges in terms of its stability, safety, and reaction controllability in atmospheres such as N2 and during the ALD atomic layer deposition process. 3. The strategy of electric field and magnetic field regulation, although effective, the inconvenience of magnetic field setting and high cost in practical applications limit the application of this strategy. 4. In the solid-state electrolyte strategy, the low lithium ion conductivity of solid-state electrolytes, their limitations in use at low and normal temperatures, high interfacial impedance, and weak adhesion to electrodes still restrict their development. 5. In the electrolyte modification strategy, ① in the electrolyte additive solution, the high cost of fluorinated electrolytes and the toxicity of fluorine-containing substances also pose challenges to its development. ② In the high-concentration electrolyte solution, the high concentration of the electrolyte will produce high viscosity, reducing the migration rate of lithium ions.The production economy of lithium salts requires reducing the cost of lithium salts. Although high salt concentration provides a stable and safe operation route for lithium anodes, the high cost problem brought by high salt concentration also poses challenges to its development. ③ In the nano-structured electrolyte solution scheme, its preparation process is relatively complex, and the material cost increases during actual application. This also limits its development. ④ In the electrolyte additive scheme, for example, adding Cs. + Ions, the strategy of forming an ion shield, due to the serious concentration dependence of additives, the actual application effect needs to be optimized.

[0004] In summary, the current methods for suppressing lithium dendrites, such as three-dimensional electrode substrates, artificial SEI, magnetic field regulation, solid electrolytes, and electrolyte modification, all have problems such as high cost, low safety, complex devices, and low ionic conductivity. SUMMARY OF THE INVENTION

[0005] Based on this, the present invention provides a preparation method of a battery electrode based on protein modification and a metal battery to solve the technical problems such as high cost, low safety, complex devices, and low ionic conductivity existing in the existing metal negative electrode modification and dendrite suppression technologies.

[0006] To achieve the above object, the present invention provides a battery electrode based on protein modification, which includes the following steps:

[0007] 1) Dissolve the protein in a buffer solution to prepare precursor A;

[0008] 2) Dissolve the reducing agent in a buffer solution to prepare precursor B;

[0009] 3) Mix precursor A and precursor B to prepare a mixed solution;

[0010] 4) Cover the electrode substrate on the surface of the mixed solution obtained in step 3), and incubate at room temperature in an air atmosphere to form a protein modification layer on the surface of the electrode substrate, obtaining a protein-modified electrode substrate;

[0011] 5) Take out, wash, and dry the protein-modified electrode substrate obtained in step 4) to obtain a protein-modified battery electrode.

[0012] As a further preferred technical solution of the present invention, the protein is one or a mixture of several of lysozyme, lipase, and polygalacturonase.

[0013] As a further preferred technical solution of the present invention, the reducing agent is a thiol reducing agent, and the thiol reducing agent includes one or a mixture of several of tris(2-carboxyethyl)phosphine, dithiothreitol, and cysteine.

[0014] As a further preferred technical solution of the present invention, the buffer solution is Tris-HCl reagent.

[0015] As a further preferred technical solution of the present invention, the electrode substrate is a copper foil, an aluminum foil or a titanium foil serving as a battery current collector, or a metal sheet made of zinc.

[0016] As a further preferred technical solution of the present invention, in step 2), the pH value of the precursor B is adjusted to 6-8 by using an alkaline solution, and the alkali in the alkaline solution is one or a mixture of several of sodium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, ammonia water, and lithium hydroxide.

[0017] As a further preferred technical solution of the present invention, in step 3), the precursor A and the precursor B are mixed according to a mass ratio of protein to reducing agent of 1:10 to 10:1.

[0018] As a further preferred technical solution of the present invention, in step 4), the incubation treatment time is 30-50 minutes. After incubation, the electrode substrate is first washed with deionized water multiple times and then dried at 40-50°C.

[0019] As a further preferred technical solution of step 4), it specifically further includes: after washing and drying, a metal layer is deposited on the surface of the protein-modified electrode substrate through an electrodeposition process, and the material of the metal layer is lithium metal, sodium metal, zinc metal, aluminum metal or magnesium metal.

[0020] According to another aspect of the present invention, the present invention also provides a metal battery. The metal battery uses a battery electrode prepared by a method for preparing a battery electrode based on protein modification. The battery electrode is a battery negative electrode or a battery positive electrode, and the metal battery is a lithium metal battery, a sodium metal battery, a zinc metal battery, an aluminum metal battery or a magnesium metal battery.

[0021] The method for preparing a battery electrode based on protein modification and the metal battery of the present invention, by adopting the above technical solutions, can achieve the following beneficial effects:

[0022] 1) The present invention uses protein to modify a battery electrode (battery positive electrode or battery negative electrode). Through the confinement effect of the channels formed by self-assembly and the adsorption effect of polar functional groups in the protein on lithium ions, the uniform flux of lithium ions and the promotion of the desolvation process of lithium ions are realized. Uniform lithium atom nucleation, deposition and growth can be achieved, effectively inhibiting the growth of dendrites, and excellent electrochemical performance is shown in both Li-Cu asymmetric batteries and Li-LiFePO4 full batteries;

[0023] 2) The preparation method of the present invention has easily available raw materials, mild reaction conditions without pollution, low cost, and convenient operation, making it suitable for large-scale production.

[0024] 3) The modification method of the present invention lays a foundation for the application of biomaterials in the field of electrochemistry and provides guidance for the modification of other similar materials and battery systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0026] Figure 1 It is a cross-sectional scanning electron microscope image of the protein modification layer prepared in Example 1 of the present invention;

[0027] Figure 2 It is a surface transmission electron microscope image of the protein modification layer prepared in Example 1 of the present invention;

[0028] Figure 3 It is a cryo-electron microscope image of the protein modification layer prepared in Example 1 of the present invention inducing spherical lithium nucleation;

[0029] Figure 4 It is a cross-sectional scanning electron microscope image of the battery negative electrode prepared in Example 1 of the present invention achieving dense and dendrite-free lithium deposition;

[0030] Figure 5 It is a battery performance graph of the battery negative electrode prepared in Example 1 of the present invention achieving ultra-long Li-Cu battery cycling;

[0031] Figure 6 It is a battery performance graph of the battery negative electrode prepared in Example 1 of the present invention achieving ultra-long Li-Cu battery cycling at different current densities, cycling capacities, and electrolytes;

[0032] Figure 7 It is a battery performance graph of the battery negative electrode prepared in Example 1 of the present invention achieving ultra-long Li-LiFePO4 full battery cycling with a low lithium loading (negative electrode capacity / positive electrode capacity is 3:1).

[0033] The realization of the object, functional features, and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the drawings. SPECIFIC EMBODIMENTS

[0034] The present invention will be further described below in conjunction with the drawings and specific embodiments. Terms such as "upper", "lower", "left", "right", "middle", and "one" used in the preferred embodiments are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships shall also be regarded as the scope of implementation of the present invention without substantial changes in the technical content.

[0035] The electrode substrate of the present invention refers to: an inactive conductive metal substrate that supports the positive or negative active material, which is not electrochemically active and does not participate in chemical reactions during the charging and discharging processes of the battery, but only serves to support the active material and conduct electricity.

[0036] In the following examples, the battery negative electrode modified by protein is taken as an example.

[0037] Example 1

[0038] (1) Lysozyme with a concentration of 20 mg / mL was dissolved in Tris-HCl reagent (pH = 7.4) to prepare precursor A.

[0039] (2) Tris(2-carboxyethyl)phosphine with a concentration of 50 mM was dissolved in Tris-HCl reagent (pH = 7.4) to prepare precursor B, and the pH was adjusted to 7 with 5 M NaOH solution.

[0040] (3) Precursor A and precursor B were fully mixed at a mass ratio of protein to reducing agent of 1.395:1 to obtain a mixed solution. Then, a 80-μm Cu electrode substrate (copper foil) was covered on the surface of the mixed solution and incubated at room temperature in an air atmosphere for 30 minutes to obtain a protein-modified electrode substrate.

[0041] (4) The protein-modified electrode substrate was taken out from the surface of the mixed solution, washed several times with deionized water, dried at 40 °C, and then a certain capacity (the negative electrode capacity / positive electrode capacity in the metal battery is 3:1) of lithium metal was deposited on the surface of the protein-modified electrode substrate by electroplating lithium metal to obtain a battery negative electrode based on protein modification.

[0042] (5) The battery negative electrode based on protein modification was applied and assembled into three metal batteries: Li-Cu, Li-Li, and Li-LiFePO4. Under the condition of small lithium deposition, the battery performance was tested, and the test results are shown in Table 1 and Table 2.

[0043] The following performance tests were carried out on the battery negative electrode and metal battery prepared in Example 1 respectively:

[0044] Refer to Figure 1 as shown, Figure 1 is the cross-sectional scanning electron micrograph of the protein modification layer prepared in Example 1 of the present invention. This figure shows that the method of using protein to modify the current collector of the battery to inhibit dendrites is convenient to prepare. The ultra-thin modification layer is only 137 nm, and the operation is convenient, which is suitable for large-scale production.

[0045] Refer to Figure 2 as shown, Figure 2This is the surface transmission electron microscopy image of the protein modification layer prepared in Example 1 of the present invention. This image shows that the protein modification layer is composed of self-assembled nanoscale spheres, and the pore channels in the middle have a confinement effect on lithium ions, providing a uniform lithium ion flux.

[0046] Refer to Figure 3 as shown Figure 3 This is the cryo-electron microscopy image of spherical lithium nucleation induced by the protein modification layer prepared in Example 1 of the present invention. This image shows that the protein modification layer can promote the spherical and uniform nucleation of lithium, which provides a basis for the subsequent uniform deposition and growth of lithium.

[0047] Refer to Figure 4 as shown Figure 4 This is the cross-sectional scanning electron microscopy image of the battery negative electrode prepared in Example 1 of the present invention, which realizes dense and dendrite-free lithium deposition. This image shows that the protein modification layer can achieve dense and uniform columnar lithium deposition, and the deposition density is close to the density of lithium metal.

[0048] Refer to Figure 5 as shown Figure 5 This is the battery performance graph of the battery negative electrode prepared in Example 1 of the present invention for realizing an ultra-long Li-Cu battery cycle. This graph shows that under the conditions of a current density of 1 mA cm -2 , and a deposition capacity of 1 mAh cm -2 , the lithium metal current collector modified by the protein modification layer can achieve up to 850 cycles and maintain a high Coulombic efficiency.

[0049] Refer to Figure 6 as shown Figure 6 This is the battery performance graph of the battery negative electrode prepared in Example 1 of the present invention for realizing an ultra-long Li-Cu battery cycle under different current densities, cycle capacities, and electrolytes. This graph shows that compared with the control Li-Cu asymmetric battery, the modified Li-Cu asymmetric battery shows significantly improved Coulombic efficiency and cycle stability. It shows that the modification method of the present invention has universality for current density, cycle capacity, and electrolyte, and this modified layer also has the ability to regulate high-current and high-capacity lithium.

[0050] Refer to Figure 7 as shown Figure 7 This is the battery performance graph of the battery negative electrode prepared in Example 1 of the present invention for realizing an ultra-long Li-LiFePO4 full battery cycle with a low lithium load (negative electrode capacity / positive electrode capacity = 3:1). This graph shows that under the conditions of a current density of 1 C and a positive electrode loading of 15.6 mg LiFePO4, under the condition of lean lithium (negative electrode capacity / positive electrode capacity = 3:1), it can stably cycle 377 times and maintain 80% of the capacity.

[0051] In the present invention, a protein-containing precursor A is reduced by a precursor B and self-assembled at the interface to modify and improve the counter electrode substrate, forming an ultra-thin protein modification layer with a thickness of only 30 - 200 nm. After modification, the weight of the electrode substrate only increases by 0.05 - 1.5 g. When this electrode substrate is used as the battery negative electrode in metal battery systems such as Li-Cu and Li-LiFePO4, the battery negative electrode achieves dendrite-free lithium deposition under the condition of lithium deficiency, and exhibits excellent electrochemical performance during multiple charge and discharge cycles, and is significantly superior to the electrochemical performance achieved by other current modification methods. 2 When used as the battery negative electrode in metal battery systems such as Li-Cu and Li-LiFePO4, the battery negative electrode achieves dendrite-free lithium deposition under the condition of lithium deficiency, and exhibits excellent electrochemical performance during multiple charge and discharge cycles, and is significantly superior to the electrochemical performance achieved by other current modification methods.

[0052] Example 2

[0053] (1) Lysozyme at a concentration of 20 mg / mL was dissolved in Tris-HCl reagent (pH = 7.4) to prepare precursor A.

[0054] (2) Dithiothreitol at a concentration of 50 mM was dissolved in Tris-HCl reagent (pH = 7.4) to prepare precursor B, and the pH of precursor B was adjusted to 7 with 5 M NaOH solution.

[0055] (3) Precursor A and precursor B were thoroughly mixed at a mass ratio of protein to reducing agent of 3:1, and then a 10-μm titanium electrode substrate (titanium foil) was covered on the surface of the mixed solution, and incubated at room temperature in an air atmosphere for 30 minutes to obtain a protein-modified titanium sheet.

[0056] (4) The protein-modified titanium sheet was taken out from the surface of the mixed solution, washed repeatedly with deionized water, dried at 40°C, and a certain amount of zinc metal (at a ratio of negative electrode capacity to positive electrode capacity of 1:1 in the metal battery) was deposited on the surface of the protein-modified electrode substrate by electro-depositing zinc metal to obtain a battery negative electrode based on protein modification.

[0057] (5) The battery negative electrode based on protein modification was applied and assembled into Zn-Ti, Zn-Zn, and Zn-MnO2 zinc metal batteries, and basic battery performance tests were carried out. The test results are shown in Table 1.

[0058] Example 3

[0059] (1) Lipase at a concentration of 20 mg / mL was dissolved in Tris-HCl reagent (pH = 7.4) to prepare precursor A.

[0060] (2) Dithiothreitol at a concentration of 100 mM was dissolved in Tris-HCl reagent (pH = 7.4) to prepare precursor B, and the pH of precursor B was adjusted to 7 with 5 M NaOH solution.

[0061] (3) The precursor A and precursor B are fully mixed at a mass ratio of protein to reducing agent of 5:1 to obtain a mixed solution. Then, a 50-μm aluminum electrode substrate (aluminum foil) is covered on the surface of the mixed solution and incubated at room temperature in an air atmosphere for 40 minutes to obtain a protein-modified electrode substrate, that is, a protein modification layer is formed on the surface of the aluminum electrode substrate.

[0062] (4) The protein-modified electrode substrate is taken out from the surface of the mixed solution, washed repeatedly with deionized water, dried at a temperature of 50 °C, etc., and a certain capacity (according to the negative electrode capacity / positive electrode capacity in the metal battery of 5:1) of sodium metal is deposited on the surface of the protein-modified electrode substrate by electro-depositing sodium metal to obtain a battery negative electrode based on protein modification.

[0063] (5) The battery negative electrode based on protein modification is applied and assembled into Na-Al, Na-Na, and Na-Na3V2(PO4)3 sodium metal batteries, and the basic battery performance is tested. The test results are shown in Table 1.

[0064] Example 4

[0065] (1) 20 mg / mL of polygalacturonase is dissolved in Tris-HCl reagent (PH = 7.4) to prepare precursor A.

[0066] (2) 100 mM of cysteine is dissolved in Tris-HCl reagent (PH = 7.4) to prepare precursor B, and the PH of precursor B is adjusted to 7 with 5M NaOH solution.

[0067] (5) The precursor A and precursor B are fully mixed at a mass ratio of protein to reducing agent of 1:5 to obtain a mixed solution. Then, a 10-μm aluminum metal electrode substrate (aluminum foil) is covered on the surface of the mixed solution and incubated at room temperature in an air atmosphere for 50 minutes to obtain a protein-modified electrode substrate.

[0068] (6) The protein-modified electrode substrate is taken out from the surface of the mixed solution, washed repeatedly with deionized water, dried at a temperature of 50 °C, etc., for subsequent use, and then a certain capacity (according to the negative electrode capacity / positive electrode capacity of the metal battery of 1:1) of potassium metal is deposited on the surface of the protein-modified electrode substrate by electro-depositing potassium metal to obtain a battery negative electrode based on protein modification.

[0069] (7) The battery negative electrode based on protein modification is applied and assembled into K-Al, K-K, and K-K3V2(PO4)3 potassium metal batteries, and the basic battery performance is tested.

[0070] Table 1. Battery Performance of Metal Batteries in Examples 1-4

[0071]

[0072]

[0073] In summary, as can be seen from Table 1: The method of protein modification and modification of metal substrates or metal electrodes helps to inhibit the generation of dendrites on the metal negative electrode and improve the cycle performance of the battery. Through physical and chemical property characterization such as scanning electron microscopy and electrochemical performance analysis, combined with Example 1, the principle of protein modification and modification of metal substrates or metal electrodes to inhibit dendrites on the metal negative electrode was explored. The mechanism analysis is as follows. The protein modification layer is a self-lubricating ion transport channel, which can promote charge transfer and mass transfer in the system.

[0074] Specifically: 1. The abundant polar functional groups on the protein surface achieve self-lubrication of lithium ions, promote charge transfer kinetics, reduce the energy barrier of desolvation and reduce the interfacial reaction energy barrier. 2. The porous self-lubricating channels of polar functional groups are conducive to electrolyte infiltration, increase the contact angle, and promote the formation of excellent SEI. The channel structure and SEI jointly promote lithium ion transport kinetics and uniform lithium ion flux, and regulate the lithium ion concentration field. Regulate mass transfer. 3. The uniform nanoscale pore structure in the middle of the protein layer can regulate the ion concentration field, uniform the ion concentration gradient, and regulate mass transfer kinetics. Furthermore, it regulates the nucleation, dense columnar deposition and uniform growth kinetics of lithium metal spheres. 4. The protein layer is always located on the surface of lithium metal during the subsequent metal deposition and stripping process, and its physical and chemical properties are stable. It has universality for different current densities, cycle capacities and electrolytes during the battery cycle. Under the above various conditions, the metal electrode can be modified to achieve excellent electrochemical performance, and this modified layer also has the ability to regulate high current and high capacity lithium. 5. Finally, the Li-Cu asymmetric battery exhibits excellent cycle performance and Coulomb efficiency. Specifically, under various conditions of current density, capacity and electrolyte, it shows far better Coulomb efficiency and cycle stability than the control sample. The Li-LiFePO4 full battery exhibits extremely long cycle performance of the Li-LiFePO4 full battery under the condition of low lithium loading (the negative electrode capacity / positive electrode capacity is 3:1). Under the condition of a current density of 1C and a positive electrode loading of 15.6 mg LiFePO4, it can stably cycle 377 times and maintain 80% of the capacity.

[0075] This modification method realizes the inhibition of dendrites and excellent battery performance. The preparation method is simple, the raw materials are easy to obtain, the reaction is mild and pollution-free, the cost is low, and the operation is convenient, which is suitable for large-scale production. It lays a foundation for the application of biological materials in the field of electrochemistry and provides guidance for the modification of other similar materials and battery systems.

[0076] Table 2. Battery performance of the Li-Cu metal asymmetric battery in Example 1

[0077]

[0078]

[0079] Note: Ether is an ether-based electrolyte, Li-S 042, specifically 1M LiTFSI dissolved in a 1:1 volume ratio of DOL / DME containing 5% LiNO3 additive; Carbonate is an ester-based electrode liquid, LX-257, specifically 1M LiPF6 dissolved in a volume ratio of 2:2:6 of FEC / HFE / FEMC.

[0080] It should be noted here that the present invention can also directly modify the electrode substrate of zinc metal material through protein modification without using electrodeposition. Since lithium, sodium, and potassium metals cannot be directly immersed in water, but zinc metal can, therefore, the zinc metal modified with protein can be directly used to assemble the metal battery.

[0081] The present invention realizes the regulation of charge transfer and mass transfer kinetics during the battery process. Specifically, the polar functional groups in the protein promote the desolvation of lithium ions at the interface and promote charge transfer kinetics; the polar functional groups and uniform channel structure in the protein are conducive to achieving excellent SEI. The channel structure and SEI jointly promote lithium ion transport kinetics and uniform lithium ion flux, and regulate the lithium ion concentration field. It can regulate the uniform lithium atom nucleation, deposition, and growth kinetics, achieving the effect of effectively inhibiting the growth of dendrites, and showing excellent electrochemical performance in asymmetric batteries such as Li-Cu, Zn-Ti, Na-Al, K-Al, symmetric batteries such as Li-Li, Zn-Zn, Na-Na, K-K, and all-solid-state batteries such as Li-LiFePO4, Zn-MnO2, Na-Na3V2(PO4)3, K-K3V2(PO4)3.

[0082] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The protection scope of the present invention is only defined by the appended claims.

Claims

1. A preparation method of a battery electrode based on protein modification, characterized in that, It includes the following steps: 1) Dissolve the protein in a buffer solution to prepare precursor A; 2) Dissolve the reducing agent in a buffer solution to prepare precursor B; 3) Mix precursor A and precursor B to prepare a mixed solution; 4) Cover the electrode substrate on the surface of the mixed solution obtained in step 3), and incubate at room temperature in an air atmosphere to form a protein modification layer on the surface of the electrode substrate, obtaining a protein-modified electrode substrate; 5) Take out, wash, and dry the protein-modified electrode substrate obtained in step 4) to obtain a protein-modified battery electrode; wherein, the protein is one or a mixture of several of lysozyme, lipase, and polygalacturonase; the reducing agent is a thiol reducing agent, and the thiol reducing agent includes one or a mixture of several of tris(2-carboxyethyl)phosphine, dithiothreitol, and cysteine; the electrode substrate is a copper foil, aluminum foil, or titanium foil serving as a battery current collector, or a metal sheet made of zinc; In step 2), the pH value of precursor B is adjusted to 6-8 using an alkaline solution, and the alkali in the alkaline solution is one or a mixture of several of sodium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, ammonia water, and lithium hydroxide; Step 5) specifically further includes: after washing and drying, a metal layer is deposited on the surface of the protein-modified electrode substrate through an electrodeposition process, and the material of the metal layer is lithium metal, sodium metal, zinc metal, aluminum metal, or magnesium metal.

2. The preparation method of the battery electrode based on protein modification according to claim 1, characterized in that, The buffer solution is a tris(hydroxymethyl)aminomethane hydrochloride Tris-HCl reagent.

3. The preparation method of the battery electrode based on protein modification according to claim 1, wherein, In step 3), precursor A and precursor B are mixed at a mass ratio of protein to reducing agent of 1:10 to 10:

1.

4. The preparation method of the battery electrode based on protein modification according to claim 1, wherein, In step 4), the incubation time is 30-50 minutes. After incubation, the electrode substrate is first washed repeatedly with deionized water and then dried at 40-50 °C.

5. A metal battery, characterized in that, The metal battery uses the battery electrode prepared by the preparation method of the protein-modified battery electrode according to any one of claims 1-4. The battery electrode is a battery negative electrode or a battery positive electrode, and the metal battery is a lithium metal battery, a sodium metal battery, a zinc metal battery, an aluminum metal battery, or a magnesium metal battery.

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