Current collector based on DNA coating and preparation method and application thereof

Abstract

The invention relates to a current collector based on DNA coating and a preparation method and application thereof, and belongs to the technical field of lithium batteries. The preparation method of the current collector based on DNA coating comprises the following steps: (1) adding aloe gel tissue into an SDS (Sodium Dodecyl Sulfate) buffer solution for cracking to obtain a cracking solution, then adding a NaCl solution for treatment, and filtering to obtain a filtrate; (2) adding an organic solvent into the filtrate for precipitation, carrying out solid-liquid separation to obtain an active substance containing DNA, and preparing a solution containing DNA; and (3) covering the surface of the silver foil with a solution containing DNA, standing, and drying to form a coating layer, thereby obtaining the current collector based on DNA coating. The silver current collector is coated with DNA extracted from aloe, strong interface bonding is achieved, lithium dendrite growth can be efficiently inhibited, the cycling stability of the lithium battery is improved, and the cruising ability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium batteries, in particular to a current collector based on DNA coating and a preparation method and application thereof. BACKGROUND

[0002] In traditional lithium batteries, copper current collectors and aluminum current collectors are often used. Copper current collectors are used for negative electrodes, have low cost and good electrical conductivity, but have problems such as heavy weight and easy oxidation. Aluminum current collectors are used for positive electrodes, are lightweight and resistant to high pressure, but have poor flexibility and are prone to corrosion.

[0003] To solve the problems of traditional copper and aluminum current collectors, researchers have proposed using composite current collectors, such as a "sandwich structure" of metal-polymer-metal (aluminum-PET-aluminum), which can improve safety and energy density, but has a high cost. The use of lightweight and highly conductive materials such as graphene and carbon nanotubes is beneficial to lightweighting, but is still in the laboratory stage and faces the problems of cost and large-scale production. Thinning the current collector and reducing the thickness of the copper / aluminum foil can reduce weight and improve energy density, but puts higher requirements on manufacturing processes such as rolling technology. Ag has unique advantages in certain battery systems (such as lithium metal batteries) due to its excellent electrical conductivity and chemical stability, but a single Ag surface is usually smooth and inert, and has weak bonding with active materials (such as sulfur, silicon, metal oxide electrodes) or electrolyte interfaces, which can easily peel off. Although Ag has excellent electrical conductivity, its interface with active materials such as conversion or alloy-type electrode materials may have poor contact or react with Li to form an insulating layer, resulting in increased interface resistance and performance degradation. The smooth bare metal surface can easily cause uneven ion deposition and dendrite growth.

[0004] To solve the problems of Ag current collectors in the prior art, it is urgent to provide an optimization strategy for Ag current collectors that can improve the interface problems of Ag current collectors, improve performance, and inhibit dendrite growth. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a current collector based on DNA coating and a preparation method and application thereof. The DNA coating current collector strategy provided by the present application can improve interface bonding, inhibit lithium dendrite growth, and improve the cycle performance of the battery.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: In a first aspect, the present application provides a preparation method of a current collector based on DNA coating, comprising the following steps: (1) Take aloe vera gel tissue and add it to a SDS buffer solution to lyse it, obtaining a lysate, then add a NaCl solution to treat it, and filter to obtain a filtrate; (2) adding an organic solvent to the filtrate to precipitate, and separating the solid and the liquid to obtain an active substance containing DNA, and configuring a solution containing DNA; (3) covering the solution containing DNA on the surface of a silver foil, and drying to form a coating layer after standing to obtain the current collector based on DNA coating.

[0007] The application provides an optimization strategy for preparing a current collector by coating a silver foil with extracted aloe DNA. First, the aloe gel tissue is subjected to cell lysis with an SDS (sodium dodecyl sulfate) buffer to release intracellular DNA and other components, then NaCl is added to remove polysaccharides by precipitation, and a filtrate containing aloe DNA is obtained, and then the active substance containing DNA is precipitated and separated, and a solution containing DNA is configured, and further coating treatment is performed on the silver foil, and after standing and drying, a current collector based on DNA coating is obtained.

[0008] The raw material selected in the application is aloe gel tissue. The aloe leaf includes epidermis, gel tissue and mucilage, the aloe gel tissue is the mesophyll part of aloe, which is located in the inside of the aloe leaf and is composed of irregular large parenchyma cells. The main source of DNA in the application is the parenchyma cells, and the pectin content of the cell wall is less, and after cell lysis, the polysaccharide and protein impurities are significantly lower than those of other sources of plant DNA (such as algal DNA) or animal DNA (such as salmon sperm DNA).

[0009] In comparison, other plant DNA extraction generally co-extracts pectin and hemicellulose (such as cactus, algae, etc.), which may have the risk of polysaccharide contamination blocking the conduction, even if the number of NaCl precipitation is increased, the residual polysaccharide will be carbonized at high temperature (battery cycle), resulting in the increase of interface resistance. Animal source DNA extraction (such as bovine thymus, salmon sperm) needs strong proteinase K digestion to remove histone, but there may still be residual histone, and the residual protein will decompose to produce NH3 under high pressure, which has the risk of corrosion.

[0010] On the other hand, the application selects Ag + The dissolved activity can realize dynamic chemical bonding with the phosphodiester bond (-PO2 - ) and the nitrogen-containing group (-NH2, -NH-, =N-, etc.) of the extracted aloe DNA, which not only buffers the charge and discharge stress, but also can induce the deposition of homogeneous lithium. The coating strategy of the application is not suitable for other current collectors, which may cause the lack of bonding force, alloying / oxidation corrosion or ion transmission blockage, and then affect the battery performance.

[0011] Meanwhile, in the active substance obtained by using the specific raw material and the above extraction method, the molecular weight of the aloe DNA is 20-50 kbp, and the molecular weight of the extracted animal DNA is mostly <10 kbp; the longer DNA molecular chain obtained by extraction is more conducive to the phosphodiester bond and the nitrogen-containing base group in the DNA molecular chain to be combined with the trace Ag dissolved from the Ag current collector + The combination results in a more compact network structure, which is conducive to the strong interface combination of the Ag current collector.

[0012] The current collector prepared by the DNA-coated current collector preparation method can realize strong interface combination, induce the deposition of homogeneous lithium, reduce the growth of lithium dendrites, comprehensively improve the cycle stability of the battery, and enhance the endurance.

[0013] Preferably, in step (1), the aloe gel tissue is first pretreated, and the pretreatment is washing away mucilage, and then cutting, grinding into paste.

[0014] Preferably, in step (1), the reaction condition of the lysis is 55-65℃ for 10-20 minutes, and mixing once every 4-6 minutes. Preferably, in step (1), the treatment condition of adding the NaCl solution is ice bath for 8-12 minutes.

[0015] NaCl can combine with the negatively charged pectin at 0℃ to accelerate the formation of precipitate, so as to remove polysaccharides by filtration.

[0016] Preferably, in step (1), the volume of the SDS buffer solution is 4-6 times the volume of the aloe gel tissue. Preferably, in step (1), the mass volume percentage of SDS in the SDS buffer solution is 1.5-2.5%.

[0017] Further preferably, the mass volume percentage of SDS in the SDS buffer solution is 2%.

[0018] The optimized SDS concentration can sufficiently dissolve the cell membrane and does not damage the DNA phosphodiester bond skeleton.

[0019] Preferably, in step (1), the volume of the NaCl solution is 5-15% of the volume of the lysis solution. Preferably, in step (1), the concentration of NaCl in the NaCl solution is 2.0-2.5 moL / L.

[0020] Preferably, in step (2), the organic solvent includes at least one of isopropyl alcohol and ethanol. Further preferably, the organic solvent is pre-cooled organic solvent. As a preferred solution, isopropanol is selected as the organic solvent, and the added volume is equal to the volume of the filtrate; and ethanol is selected as the organic solvent, and the added volume is twice the volume of the filtrate.

[0021] Preferably, in step (2), the precipitation temperature is -20-0°C and the precipitation time is 20-30 minutes. Slow precipitation can maintain the DNA in a stretched long chain configuration and achieve a molecular weight retention rate of >95%, thereby obtaining DNA molecules with longer chain lengths.

[0022] Preferably, in step (2), the solid-liquid separation is specifically: centrifuging at a speed of 11000-12000 rpm for 5-6 minutes and removing the supernatant; Preferably, in step (2), after precipitation and solid-liquid separation, washing and drying steps are further included to obtain active substance powder containing DNA, which is configured into a solution containing DNA.

[0023] After adding an organic solvent and precipitating at low temperature, the DNA forms a white flocculent precipitate. The supernatant is removed by centrifugation to obtain a moist active substance precipitate containing DNA. Further washing to remove salt and drying to remove water can obtain DNA with higher purity.

[0024] Further preferably, the washing is performed by washing with a 70% ethanol aqueous solution, and the drying is performed by placing the sample in a vacuum drying oven at 25° C. for 24 hours.

[0025] Preferably, in step (3), the concentration of the active substance containing DNA in the solution containing DNA is 1.5-2.5 mg / ml; Preferably, in step (3), the silver foil is fully immersed in the solution containing DNA prepared in step (2) to achieve coverage; Preferably, in step (3), the standing time is 15-25 minutes.

[0026] Preferably, in step (3), the drying is performed by placing the product in a vacuum drying oven at 25° C. for 24 hours.

[0027] Preferably, in step (3), the thickness of the coating layer is 1.1-1.3 μm.

[0028] In a second aspect, the present invention provides a DNA-coated current collector prepared by the above-mentioned DNA-coated current collector preparation method.

[0029] Preferably, the DNA-coated current collector comprises a silver foil substrate and a DNA layer covering at least one side of the silver foil substrate.

[0030] In a third aspect, the present invention provides the use of the above-mentioned DNA-coated current collector in a lithium battery.

[0031] Compared with the prior art, the present application has the following beneficial effects: The present application provides a DNA-coated current collector preparation method. By adopting a specific DNA extraction step, a directional impurity removal-conformation protection-zero-pollution residual trinity processing system is established. The extracted DNA is coated on silver foil to form a coating layer, thereby realizing the preparation of DNA-coated silver current collector of aloe, and obtaining a DNA coating layer with strong interface bonding and high efficiency in inhibiting lithium dendrite growth, which is applied to batteries to comprehensively improve the use performance. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Fig. 1 is a SEM image of the surface of the current collector in (a) Comparative Example 1 and (b) the DNA-coated current collector in Example 1; Fig. 2 is a SEM image of the surface of the current collector after plating lithium in (c) Comparative Example 1 and (d) the DNA-coated current collector in Example 1; Figure 2 Fig. 3 is a cycle coulombic efficiency result graph of the half-cell assembled by the current collector in Example 1 and Comparative Example 1; Figure 3 Fig. 4 is a polarization voltage result graph of the symmetric cell assembled by the current collector in Example 1 and Comparative Example 1 during the cycle process; Figure 4 Fig. 5 is a voltage-time result graph of the half-cell 10 cycle in (a) Example 1 and Comparative Example 1 and (b) a partial enlarged view of the results in the red box in the voltage-time result graph (a) of the half-cell 10 cycle in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0033] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific embodiments. In the following examples, the test methods used are conventional methods unless otherwise specified; and the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0034] Example 1 One embodiment of the DNA-coated current collector and the preparation method thereof according to the present application is described in the present embodiment. The DNA-coated current collector preparation method according to the present embodiment is as follows: (1) Raw material pretreatment, cell lysis and impurity removal Aloe vera was purchased from the Jingdong e-commerce platform, the epidermis was removed, fresh aloe gel tissue was scraped, and the surface mucus was washed away with sterile water. The sample was cut, ground and made into a paste; Add 5 times the volume of the sample of SDS buffer solution, and treat in a 60°C water bath for 15 minutes to lyse, mix thoroughly every 5 minutes to ensure complete reaction, wherein the mass percentage of SDS in the SDS buffer solution is 2%, to obtain a lysate; Add a NaCl solution with a volume of 10% of the volume of the lysate, and treat in an ice bath for 10 minutes, wherein the concentration of the NaCl solution is 2.0 moL / L, and the solution is observed to become turbid, and is filtered with a filter screen, and the filtrate is retained.

[0035] (2) Precipitation of DNA, solid-liquid separation, and preparation of a coating solution Add an equal volume of pre-cooled isopropyl alcohol to the filtrate obtained in step (1), and mix gently, and stand at -20°C for 20 minutes to cause the DNA to form a white flocculent precipitate; Set the centrifuge parameters to 12000 rpm, and centrifuge for 5 minutes, and discard the supernatant to obtain a precipitate containing DNA, and wash with 70% ethanol to remove salt, and after brief centrifugation, discard the ethanol, and place the precipitate in a vacuum drying oven at 25°C to dry for 24 hours, to obtain a DNA-containing powder; Weigh 20 mg of the powder, add 10 mL of deionized water, and mix to prepare a solution with a concentration of 2 mg / mL.

[0036] (3) Forming a DNA coating layer on a silver foil Prepare a silver foil with a size of 5 cm x 5 cm, and fully immerse it in the DNA-containing solution prepared in step (2), and stand for 20 minutes to allow the DNA molecules to fully coat the surface of the silver foil, and then wash the surface with deionized water to remove excess solution, and then place in a vacuum drying oven at 25°C to dry for 24 hours, to obtain the DNA-coating-based current collector.

[0037] Observe the surface coating layer of the DNA-coating-based current collector prepared in this example by scanning electron microscopy (SEM), and the thickness is 1.2 μm, as shown in Figure 1 (b), and it can be seen that a dense DNA coating layer is formed on the surface of the current collector.

[0038] Example 2 Example 2 differs from Example 1 only in that in step (1), the mass percentage of SDS in the SDS buffer solution used for cell lysis is 2.5%.

[0039] Example 3 Example 3 differs from Example 1 only in that in step (2), after adding the organic solvent, the precipitation conditions are to stand in an ice bath for 30 minutes.

[0040] Example 4 Example 4 differs from Example 1 only in that in step (2), 15 mg of the dried powder is weighed and added to 10 mL of deionized water to prepare a DNA-containing solution with a concentration of 1.5 mg / mL.

[0041] Comparative Example 1 The current collector of Comparative Example 1 is the same silver foil as in step (3) of Example 1, but without coating treatment.

[0042] The surface of the silver foil is observed by scanning electron microscopy (SEM), as shown in Figure 1 (a), the surface of the untreated silver foil can be seen to be smooth.

[0043] Comparative Example 2 Comparative Example 2 differs from Example 1 only in that the raw material for DNA extraction is replaced by edible cactus purchased from the Jingdong e-commerce platform, and the fleshy stem is peeled and extracted to obtain a cactus DNA-coated Ag current collector.

[0044] Comparative Example 3 Comparative Example 3 differs from Example 1 only in that the commercially available calf thymus DNA is prepared into a solution of the same concentration by adding water, replacing the extracted DNA solution, and directly performing the coating operation in step (3) to obtain a calf thymus DNA-coated Ag current collector.

[0045] Comparative Example 4 Comparative Example 4 differs from Example 1 only in that the silver foil in step (3) is replaced by aluminum foil.

[0046] Effect Example To explore the application performance of the DNA-coated current collector provided by the application and the effectiveness of the preparation method thereof, the following tests are performed: 1. Lithium plating: the current collectors in the examples and comparative examples are plated with lithium, with a current density of 1 mA·cm -2 , and a surface capacity of 3 mAh·cm -2 . The surface morphology of the current collectors after lithium plating in Example 1 and Comparative Example 1 is analyzed by SEM, and the results are shown in Figure 1 (c-d); 2. Half-cell assembly: Current collector: the current collectors in the above examples and comparative examples are used; Active material layer: mass ratio of active material LiCoO2: conductive agent Super P: binder PVDF = 8:1:1, coated on the current collector to obtain a working electrode; Electrolyte: lithium-sulfur electrolyte; Counter electrode: lithium metal sheet; Separator: Celgard2325 (PP / PE / PP three layers); Battery case: CR2032 button battery case; Assembly sequence: negative electrode case, lithium sheet, electrolyte (40 μL), separator, electrolyte (40 μL), working electrode, gasket, spring sheet, positive electrode case.

[0047] 3. Asymmetric battery assembly: Current collector: the current collectors in the above examples and comparative examples were used respectively; Active material layer: mass ratio of active material LiCoO2: conductive agent Super P: binder PVDF = 8:1:1, coated on the current collector to obtain the working electrode; Electrolyte: lithium-sulfur electrolyte; Counter electrode: metal lithium sheet; Separator: Celgard2325 (PP / PE / PP three layers); Battery case: CR2032 button battery case; Assembly sequence: negative electrode case, working electrode, lithium sheet, electrolyte, separator, electrolyte, Li sheet, working electrode, positive electrode case.

[0048] 4. Cycle test conditions: the test procedure parameters are as shown in Table 1.

[0049] Table 1 Cycle test procedure parameters The 250 cycle coulombic efficiency results of the half-batteries assembled from the current collectors of Example 1 and Comparative Example 1 are as shown in Figure 2 ; the polarization voltage results of the symmetric batteries assembled from the current collectors of Example 1 and Comparative Example 1 during the cycle process are as shown in Figure 3 ; the voltage-time results of the half-batteries assembled from the current collectors of Example 1 and Comparative Example 1 for 10 cycles are as shown in Figure 4 (a-b); the interface impedance, cycle short circuit condition and 10 cycle coulombic efficiency results of the half-batteries assembled from the current collectors of Example and Comparative Example are as shown in Table 2.

[0050] 5. Histone residue: the DNA-containing powder extracted in Example and Comparative Examples 2-4 or purchased DNA was subjected to hydrochloric acid sealed hydrolysis and benzoyl chloride derivatization, and then the characteristic peak of benzamide was detected by gas chromatography to analyze whether NH3 could be detected, and the results are as shown in Table 2.

[0051] Table 2 Performance test results of Example and Comparative Example Figure 1 (c) is the SEM image of the surface of the single silver current collector plated with lithium in Comparative Example 1; Figure 1(d) is the SEM image of the surface of the lithium-plated current collector based on DNA coating in Example 1. It can be seen that the effect of lithium plating on a single Ag foil is poor, Figure 1 (c) the lithium layer cannot form a dense and continuous film, and there are obvious powder clusters or dendritic protrusions. After the lithium plating of the current collector based on DNA coating, Figure 1 (b) the lithium layer has fine particles on the surface and no obvious sharp protrusions, and presents a relatively dense accumulation state, and no powder clusters or dendritic protrusions appear, which can avoid the risk of dendrites; at the same time, the lithium layer and the silver current collector interface are closely attached, and there is no obvious gap or peeling.

[0052] From the comparison of Figures 2-4 The comparative example 1 uses a half-cell with uncoated silver foil, and after 135 cycles, the Coulomb efficiency is obviously decreased, and the efficiency of 10 cycles is 94%; while the half-cell based on the DNA-coated current collector of the present application still maintains good battery stability and Coulomb efficiency after 250 cycles, and the Coulomb efficiency of 10 cycles is 99.5%.

[0053] According to the test results of the polarization voltage, the polarization voltage of the symmetric battery prepared by the uncoated silver foil of the comparative example 1 increases obviously after 500 h in the cycle process, and the short circuit phenomenon appears; in comparison, the symmetric battery based on the DNA-coated current collector of the present application has better battery stability, and no obvious voltage rise or short circuit phenomenon appears within 700 h. From the comparison of the polarization voltage of the half-cell after amplification, it can still be seen that the polarization voltage of the half-cell using the uncoated silver foil is higher.

[0054] The above results correspond to the surface lithium layer condition of the lithium-plated current collector, and further verify that the current collector based on DNA coating provided by the present application has the advantages of efficiently inhibiting lithium dendrite growth and improving battery cycle performance.

[0055] Further comparison of the data in Table 2 shows that: The specific extraction strategy adopted in Example 1 of the present application obtains the aloe DNA-coated silver foil current collector, and the DNA is less likely to be broken during mechanical crushing, and the DNA molecular chain quality can be well preserved; at the same time, the aloe polysaccharide can be efficiently removed by NaCl selective precipitation, and compared with other plant DNA, animal DNA coating or combination with other current collectors, the interface failure, lithium consumption or safety risk can be effectively avoided, and the commercial feasibility is higher.

[0056] In comparison, the comparative example 2 uses cactus DNA coating, and compared with the cell wall of aloe gel tissue, the cactus succulent stem cell wall contains more lignin, and the mucopolysaccharide (such as arabinogalactan) extraction process of cactus is difficult to remove completely, and the polysaccharide carbonizes during the high-temperature battery cycle process, causing the interface resistance to rise;​ Comparative Example 3 uses commercially available animal DNA coating, in which residual proteins are decomposed to produce NH3 under high pressure, which poses a long-term corrosion risk; the plant DNA used in the present application itself contains a higher abundance of guanine-cytosine (GC) base pairs that can form a dense nitrogen coordination network, giving it unique lithium ion affinity; at the same time, the plant cell wall polysaccharide fragments such as hemicellulose derivatives remaining in the phosphodiester bond skeleton of the DNA can mediate dynamic lithium ion solvation through hydroxyl groups, and also serve as a mechanical buffer layer to alleviate electrode volume change stress, with even better results; In Comparative Example 4, aluminum foil is used for preparation, and an Al2O3 passivation film will be generated on the surface of Al, causing a sharp rise in interface impedance, and Al itself has smaller electrical conductivity and lower coulomb efficiency, so the performance of aluminum foil cannot be improved well, and it is not suitable for the technical solution of the present application.

[0057] In summary, the specific extraction process provided by the present application establishes a three-in-one process system of directional impurity removal-conformation protection-zero pollution residue for aloe gel tissue DNA, which is conducive to forming a DNA coating layer to achieve strong interface bonding + efficient dendrite inhibition, further enhances the interface strength through chemical bonding with silver current collectors, can efficiently inhibit lithium dendrite growth, and is applied to batteries to comprehensively improve the cycle performance and increase the endurance, providing a new idea for solving the application defects of single current collector in the prior art.

[0058] Finally, it should be explained that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing a current collector based on DNA coating, characterized in that: The following steps are involved: (1) Take aloe vera gel tissue and add it to SDS buffer for lysis to obtain lysate, then add NaCl solution for treatment and filter to obtain filtrate; (2) adding an organic solvent to the filtrate for precipitation, separating the solid and liquid to obtain an active substance containing DNA, and preparing a solution containing DNA; (3) Covering the surface of the silver foil with the solution containing DNA, allowing it to stand and then dry to form a coating layer, thereby obtaining the DNA-coated current collector.

2. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (1), the reaction conditions for the cleavage are: reaction at 55-65°C for 10-20 minutes, and mixing every 4-6 minutes; And / or, in step (1), the condition for adding NaCl solution treatment is ice bath for 8-12 minutes.

3. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (1), the volume of the SDS buffer is 4-6 times the volume of the aloe vera gel tissue; And / or, in step (1), the mass volume percentage of SDS in the SDS buffer is 1.5-2.5%.

4. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (1), the volume of the NaCl solution is 5-15% of the volume of the lysate; And / or, in step (1), the concentration of NaCl in the NaCl solution is 2.0-2.5 mol / L.

5. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (2), the organic solvent includes at least one of isopropanol and ethanol; And / or, in step (2), the precipitation temperature is -20-0°C, and the precipitation time is 20-30 minutes.

6. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (2), the solid-liquid separation is specifically as follows: centrifuging at a speed of 11000-12000 rpm for 5-6 minutes and removing the supernatant; And / or, in step (2), after precipitation and solid-liquid separation, washing and drying steps are further included to obtain a powder containing DNA, which is then configured into a solution containing DNA.

7. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (3), the concentration of the active substance containing DNA in the solution containing DNA is 1.5-2.5 mg / ml; And / or, in step (3), the standing time is 15-25 minutes.

8. The method for preparing a DNA-coated current collector according to claim 1, wherein: In step (3), the thickness of the coating layer is 1.1-1.3 μm.

9. A DNA-coated current collector prepared by the DNA-coated current collector preparation method according to any one of claims 1 to 8.

10. Use of the DNA-coated current collector according to claim 9 in a lithium battery.

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