Method for reconstructing structure of positive electrode material of waste lithium ion battery with assistance of multidimensional molecular engineering

Abstract

The application relates to the technical field of electrode structure reconstruction, and discloses a method for reconstructing the structure of a positive electrode material of a waste lithium ion battery with the assistance of multi-dimensional molecular engineering. The method adopts a chlorogenic acid-mannan grafted product to modify a collagen fiber biological template to mediate the lithium battery positive electrode material, a three-dimensional skeleton is formed, nano zirconium dioxide crystals are filled, finally, a nano coating technology is adopted to improve the electrical performance of the electrode, prolong the service life of the battery, and improve the safety performance. The method is simple in preparation process and green and safe. The performance of the battery electrode after electrode reconstruction is obviously improved, and the waste lithium battery is reused.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrode structure reconstruction, in particular to a method for reconstructing the structure of a positive electrode material of a waste lithium ion battery with the assistance of multidimensional molecular engineering. BACKGROUND

[0002] With the development of batteries by humans, lithium batteries have become energy storage devices for mobile phones, computers, unmanned aerial vehicles and new energy vehicles. The lithium battery assisted by multidimensional molecular engineering is endowed with higher ion transmission, electronic conductivity, rate performance and cycle stability due to the nanometer two-dimensional layered structure. With the passage of time, the interface side reaction between the electrode and the electrolyte will form a solid electrolyte interface layer on the surface of the electrode. With the accumulation of time, the interface layer will become thicker, thereby affecting ion transmission. Due to the differences in the chemical and physical properties of the high molecular material assisted by the battery positive electrode material, the volume of some electrode materials expands during the charging and discharging process, resulting in unstable electrode structure, reduced battery capacity and serious safety hazards.

[0003] Chinese patent application No. CN 118800992 A discloses a method for reconstructing the layered structure of a lithium battery storage failure high-nickel positive electrode material. The storage failure ternary layered high-nickel positive electrode material is subjected to heat treatment. The positive electrode material, the conductive agent and the binder are put into N-methyl pyrrolidone and mixed and stirred. The slurry is coated on an aluminum foil, and a hot roller is pressed to form a lithium battery positive electrode sheet. The method is fast, simple and easy to operate, but the technology is single, and the electrode performance cannot be effectively improved, thereby further improving the battery performance and prolonging the service life.

[0004] Therefore, it is particularly important to provide a method for reconstructing the interface structure of a waste lithium battery positive electrode material with the assistance of multidimensional molecular engineering, recovering the electrical performance of the lithium battery and prolonging the service life of the battery. SUMMARY

[0005] The application aims to provide a method for reconstructing the structure of a waste lithium ion battery positive electrode material with the assistance of multidimensional molecular engineering. The method uses a chlorogenic acid-mannan graft product to modify a collagen fiber biomatrix to mediate the lithium battery positive electrode material. A three-dimensional skeleton is formed, nano zirconium oxide crystals are filled, the structure of the waste battery positive electrode is reconstructed, and finally a nano silver coating wrapping technology is used to prolong the service life of the electrode and improve the overall safety performance of the battery.

[0006] To achieve the above-mentioned purpose, the application provides a method for reconstructing the structure of a waste lithium ion battery positive electrode material with the assistance of multidimensional molecular engineering, which comprises the following steps:

[0007] In step S1, chlorogenic acid and mannose are dissolved in a first solvent, an acid solution and an initiator are added, and a chlorogenic acid-mannan graft product is obtained by reaction.

[0008] Step S2, dissolving the chlorogenic acid-mannan and collagen fiber in a second solvent, adding glutaraldehyde, and reacting to obtain a chlorogenic acid-mannan modified collagen fiber;

[0009] Step S3, dispersing the chlorogenic acid-mannan modified collagen fiber in a saturated sodium chloride solution, adding an acid solution and stirring for the first time, adding nano zirconium dioxide, and stirring for the second time to obtain a chlorogenic acid-mannan modified collagen fiber filled with nano zirconium dioxide crystals;

[0010] Step S4, mixing the waste positive electrode material powder and the chlorogenic acid-mannan modified collagen fiber filled with nano zirconium dioxide crystals, dispersing in a silver nitrate solution for silver plating, and obtaining a plated product;

[0011] Step S5, mixing the plated product with a binder, thermoplastically forming a sheet, and reconstructing a battery positive electrode sheet.

[0012] Preferably, in the step S1, the first solvent is any one or more of water, ethanol, and dimethyl sulfoxide.

[0013] Preferably, in the step S1, the acid solution is any one or more of dilute sulfuric acid and dilute hydrochloric acid.

[0014] Preferably, in the step S1, the initiator is any one or more of ammonium persulfate, azobisisobutyronitrile, and dimethyl azobisisobutyrate.

[0015] Preferably, in the step S1, the reaction temperature is 60-80°C, and the reaction time is 4-6 h.

[0016] Preferably, in the step S1, the mass ratio of the mannose, chlorogenic acid, initiator, acid solution, and first solvent is 1: (1.6-2.6): (0.013-0.108): (0.05-0.1): (3-4).

[0017] Preferably, in the step S2, the second solvent is an ionic liquid, including any one or more of 1-butyl-3-methylimidazolium chloride ionic liquid, 1-allyl-3-methylimidazolium chloride ionic liquid, and 1-ethyl 3-methyl imidazole chloride ionic liquid.

[0018] Preferably, in the step S2, the concentration of the glutaraldehyde is 3-5 mol / L, and the addition amount is 2-5 mL.

[0019] Preferably, in the step S2, the reaction temperature is 40-50°C, and the reaction time is 6-8 h.

[0020] Preferably, in the step S2, the mass ratio of the collagen fiber, the chlorogenic acid-mannan, and the second solvent is 1: (0.25-0.43): (2-3).

[0021] Preferably, in the step S3, the first stirring is performed for 3-4 h.

[0022] Preferably, in the step S3, the second stirring is performed for 5-6 h, and the temperature of the second stirring is 40-50℃.

[0023] Preferably, in the step S3, the acid solution is any one or more of dilute sulfuric acid and dilute hydrochloric acid.

[0024] Preferably, in the step S3, the mass ratio of the chlorogenic acid-mannan modified collagen fiber powder, the saturated sodium chloride solution, the acid solution, and the nano zirconium dioxide is 1: (5-10): (0.05-0.1): (0.05-0.1).

[0025] Preferably, in the step S4, the concentration of the silver nitrate ethanol solution is 1-2 mol / L, and the amount used is 30-40 mL.

[0026] Preferably, in the step S4, the silver plating process is as follows: the waste positive electrode material powder and the chlorogenic acid-mannan modified collagen fiber filled with nano zirconium dioxide crystals are mixed and dispersed in a silver nitrate solution, stirred at room temperature for 1-2 h, 10-15 g of ascorbic acid is added, and stirring is continued for 30-60 min, followed by filtration, ethanol washing, and vacuum calcination at 200-300℃ for 3-5 h.

[0027] Preferably, in the step S5, the binder is any one or more of polyvinyl alcohol, polytetrafluoroethylene, and polyvinylidene fluoride; and the mass ratio of the plated product to the binder is 1: (0.075-0.25).

[0028] Preferably, in the step S5, the thermoplastic process is as follows: the plated product mixed with the binder is coated on an aluminum foil coated with a positive electrode material, dried at 50-60℃, and hot-rolled at 130℃-180℃ and 500-800 kg / cm 2 for 200-300 s, and dried for 20-24 h.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] (1) In order to reduce the risk of volume expansion and shrinkage of the positive electrode of the battery during the cycle process, improve the service life of the battery, prevent overcharge and overdischarge of the battery, and improve the safety of the battery, the present application uses biological macromolecules as templates to synthesize nanomaterials and fill nanocrystals to restore and improve the structure and performance of the positive electrode material. The present application uses chlorogenic acid-mannan modified collagen fiber biomaterials to mediate the structure of the positive electrode material of the waste lithium battery, forms a three-dimensional network stereoscopic framework, and reconstructs and optimizes the structure of the positive electrode material of the waste lithium battery. The glycosidic bond of mannose can form a complex flexible network structure, and the phenolic hydroxyl or carboxyl in chlorogenic acid can be crosslinked with the active groups on the polysaccharide chain through esterification, etherification and other ways, which can strengthen the crosslinked network and improve its rigidity, forming a polymer with both elasticity and strength. Collagen fibers serve as the core of the framework, providing better tensile strength and elongation at break, and chlorogenic acid-mannan can improve the crosslinking density of collagen fibers, thereby improving their tensile strength and elongation at break, which is conducive to supporting. Monoclinic nanometer zirconium dioxide is filled into the gap of the three-dimensional network structure, which can optimize the distribution density, reduce the internal stress, improve the compressive capacity of the network structure, and thus improve the stability and toughness of the overall structure, enhance the conductivity of the three-dimensional network structure, and enhance the interaction between the lithium ion battery positive electrode material and the electrolyte.

[0031] (2) The present application adopts nanosilver coating technology to coat the electrode material. High nickel content in lithium batteries faces many technical challenges, such as large capacity loss during cycling, thermal structure instability, safety problems and unstable surface chemical properties. These technical problems are attributed to several mechanisms: ① nickel ions and lithium ions have similar radii, and nickel ions irreversibly migrate to lithium sites, leading to cation mixing, eventually converting the layered structure of the electrode to spinel and rock salt structure; ② residual lithium on the surface of the material reacts with water and carbon dioxide in the air to form a Li2CO3 / LiOH passivation layer, leading to the failure of the layered nickel-rich positive electrode reaction interface; ③ tetravalent nickel ions, oxygen vacancies and newly generated active oxygen species on the surface of the nickel-rich material promote the generation of strong oxidizing species through surface side reactions, leading to the dissolution of transition metals during the cycle process, increasing the interfacial resistance, and ultimately leading to capacity decay. The surface coating can effectively remove residual lithium, prevent surface side reactions, stabilize the surface structure and bulk structure, and the coating also acts as a barrier layer to avoid direct contact between the electrolyte and the cathode. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Operation flow chart of the method for reconstructing the structure of the positive electrode material of the waste lithium ion battery assisted by multi-dimensional molecular engineering.

[0033] Figure 2The first charge-discharge curves of a battery assembled using a multidimensional molecular engineering-assisted method for reconstructing the cathode material structure of spent lithium-ion batteries at a rate of 0.2C and a voltage range of 2.7–4.3 V are shown. Detailed Implementation

[0034] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0035] Unless otherwise specified, all reagents and equipment used in the following examples were purchased from commercial channels.

[0036] Example 1

[0037] like Figure 1 As shown, a method for reconstructing the structure of cathode materials from spent lithium-ion batteries assisted by multidimensional molecular engineering includes:

[0038] Step S1: Dissolve 16 g of chlorogenic acid and 10 g of mannan in 30 g of water, add 0.5 g of dilute sulfuric acid and 1 g of ammonium persulfate, and react at 60 °C for 6 h to obtain chlorogenic acid-mannan.

[0039] Step S2: Dissolve 2.5 g of chlorogenic acid-mannan and 10 g of collagen fiber in 20 g of 1-butyl-3-methylimidazolium chloride ionic liquid, add 2 mL of 5 mol / L glutaraldehyde, and react at 40℃ for 8 h to obtain chlorogenic acid-mannan modified collagen fiber.

[0040] Step S3: Disperse 10 g of chlorogenic acid-mannan modified collagen fibers in 50 g of saturated sodium chloride solution, add 0.5 g of dilute sulfuric acid and stir for 3 h, add 0.55 g of nano zirconium dioxide, and stir at 40 °C for 6 h to obtain chlorogenic acid-mannan modified collagen fibers filled with nano zirconium dioxide crystals.

[0041] Step S4: Mix the waste cathode material powder and the chlorogenic acid-mannan modified collagen fiber filled with nano-zirconia crystals, disperse it in 40 mL of 1 mol / L silver nitrate solution, stir at room temperature for 1 h, add 15 g of ascorbic acid, continue stirring for 30 min, filter, wash the solid with ethanol, and calcine under vacuum at 200℃ for 5 h to obtain the coating product.

[0042] Step S5: Mix 10 g of the coating product with 0.75 g of polyvinyl alcohol, coat the aluminum foil of the positive electrode material, and heat at 130°C and 500 kg / cm². 2 Under the conditions of hot rolling for 300 s and drying at 50℃ for 24 h, the thermoplastic form is a sheet, which is used to reconstruct the positive electrode sheet of the battery.

[0043] Example 2

[0044] As shown in Figure 1 The multi-dimensional molecular engineering assisted waste lithium ion battery positive electrode material structure reconstruction method comprises the following steps:

[0045] Step S1, 20 g of chlorogenic acid and 10 g of mannose are dissolved in 25 g of ethanol, 0 g of dilute hydrochloric acid and 0.5 g of azobisisobutyronitrile are added, and the reaction is carried out at 70°C for 5 h to obtain chlorogenic acid-mannan.

[0046] Step S2, 3.5 g of chlorogenic acid-mannan and 10 g of collagen fiber are dissolved in 25 g of 1-allyl-3-methylimidazole chloride ionic liquid, 3 mL of 4 mol / L glutaraldehyde is added, and the reaction is carried out at 50°C for 7 h to obtain chlorogenic acid-mannan modified collagen fiber.

[0047] Step S3, 10 g of chlorogenic acid-mannan modified collagen fiber is dispersed in 75 g of saturated sodium chloride solution, 0.75 g of dilute hydrochloric acid is added and stirred for 4 h, 0.75 g of nano zirconium dioxide is added, and the reaction is carried out at 50°C for 5 h to obtain nano zirconium dioxide crystal filled chlorogenic acid-mannan modified collagen fiber.

[0048] Step S4, the waste positive electrode material powder and the nano zirconium dioxide crystal filled chlorogenic acid-mannan modified collagen fiber are mixed, dispersed in 35 mL of 1.5 mol / L silver nitrate solution, stirred at room temperature for 2 h, then 15 g of ascorbic acid is added, and the stirring is continued for 45 min. Filter, wash the solid with ethanol, and calcine at 250°C for 4 h to obtain the plated product.

[0049] Step S5, 10 g of the plated product is mixed with 1 g of polytetrafluoroethylene, coated on the aluminum foil of the positive electrode material, and hot rolled at 150°C, 600 kg / cm 2 for 200 s, dried at 60°C for 22 h, and the thermoplastic type is sheet, and the battery positive electrode sheet is reconstructed.

[0050] Example 3

[0051] As shown in Figure 1 The multi-dimensional molecular engineering assisted waste lithium ion battery positive electrode material structure reconstruction method comprises the following steps:

[0052] Step S1, 26 g of chlorogenic acid and 10 g of mannose are dissolved in 30 g of dimethyl sulfoxide, 1 g of dilute hydrochloric acid and 0.13 g of dimethyl azobisisobutyrate are added, and the reaction is carried out at 80°C for 4 h to obtain chlorogenic acid-mannan.

[0053] Step S2, 4.3 g chlorogenic acid-mannan and 10 g collagen fibers were dissolved in 30 g 1-ethyl 3-methyl imidazole chloride ionic liquid, 5 mL 3 mol / L glutaraldehyde was added, and the reaction was carried out at 40°C for 6 h to obtain chlorogenic acid-mannan modified collagen fibers.

[0054] Step S3, 10 g of chlorogenic acid-mannan modified collagen fibers were dispersed in 100 g saturated sodium chloride solution, 1 g dilute sulfuric acid was added and stirred for 4 h, 1 g nano zirconium dioxide was added, and the mixture was stirred at 40°C for 5 h to obtain chlorogenic acid-mannan modified collagen fibers filled with nano zirconium dioxide crystals.

[0055] Step S4, the waste positive electrode material powder and the chlorogenic acid-mannan modified collagen fibers filled with nano zirconium dioxide crystals were mixed and dispersed in 30 mL of 2 mol / L silver nitrate solution, stirred at room temperature for 2 h, then 16 g ascorbic acid was added and stirred for 60 min, filtered, and the solid was washed with ethanol and calcined at 300°C for 3 h to obtain the plated product.

[0056] Step S5, 10 g of the plated product was mixed with 2.5 g of polyvinylidene fluoride, coated on the aluminum foil of the positive electrode material, and hot rolled at 180°C, 800 kg / cm 2 for 200 s, and dried at 60°C for 20 h to obtain a thermoplastic sheet-shaped positive electrode sheet.

[0057] Comparative Example 1

[0058] The multi-dimensional molecular engineering assisted waste lithium ion battery positive electrode material structure reconstruction method is different from Example 2 in that step (4) uses mannose modified collagen fibers.

[0059] Comparative Example 2

[0060] The multi-dimensional molecular engineering assisted waste lithium ion battery positive electrode material structure reconstruction method is different from Example 2 in that step (4) uses chlorogenic acid modified collagen fibers.

[0061] Comparative Example 3

[0062] The multi-dimensional molecular engineering assisted waste lithium ion battery positive electrode material structure reconstruction method is different from Example 2 in that step (5) does not add nano zirconium dioxide.

[0063] Comparative Example 4

[0064] The multi-dimensional molecular engineering assisted waste lithium ion battery positive electrode material structure reconstruction method is different from Example 2 in that step (6) does not perform plating.

[0065] Performance test:

[0066] The electrodes prepared in Examples 1-3 and Comparative Examples 1-4 were tested for the first discharge specific capacity and the first charge-discharge capacity ratio according to the conditions and methods specified in GB / T 23365-2023.

[0067] The electrodes prepared in Examples 1-3 and Comparative Examples 1-4 were tested for the first coulombic efficiency and the 200-cycle cycle retention rate according to the conditions and methods specified in GB / T 37207-2018.

[0068] The electrodes prepared in Examples 1-3 and Comparative Examples 1-4 were tested for the direct current internal resistance according to the conditions and methods specified in YS / T 1615-2023.

[0069] As shown in FIG. 1, FIG. 2 and FIG. 3, the electrodes recovered in Examples 1-3 and Comparative Examples 1-4 were tested for the first charge-discharge curves, the first discharge specific capacity, the coulombic efficiency and the 200-cycle cycle retention rate. Figure 2 As shown in FIG. 4, FIG. 5 and FIG. 6, the electrodes recovered in Examples 1-3 and Comparative Examples 1-4 were tested for the direct current internal resistance. Figure 2 FIG. 7 is a graph of the first charge-discharge curves of Example 2 and Comparative Examples 1-4, and the current density was 0.2 C. The coulombic efficiency was calculated according to the data of charge-discharge. As can be seen from the graph, the electrode recovered in Example 2 had the lowest charge curve, the highest discharge curve, and the highest charge and discharge specific capacity. The first discharge specific capacity of the electrodes recovered in Example 2, Comparative Examples 1-4 was 192.29 mAh g -1 , 177.72 mAh g -1 , 184.34 mAh g -1 , 176.19 mAh g -1 , 176.65 mAh g -1 ; and the coulombic efficiency was 96.15%, 91.14%, 95.51%, 92.24%, 90.20%, respectively. As can be seen from the test results, the electrode recovered in Comparative Example 3 had the lowest capacity, which was because its crystal structure was not perfect; and the electrode recovered in Comparative Example 4 had a lower coulombic efficiency, and the electrode recovered in Example 2 exhibited the best electrochemical performance, thus the method for recovering the electrode activity in Example 2 was the best.

[0070] Table 2 Electrical performance parameters of batteries assembled with different positive electrode materials

[0071]

[0072] As shown in Table 2, the performance of the positive electrode materials recovered in Examples 1-3 was better than that of Comparative Examples 1-4, which was mainly because the method in Examples 1-3 used biological template-mediated electrode materials, which filled the nano-zirconium dioxide crystals in the three-dimensional pore structure, and improved the structural integrity, and the nano-silver coating effectively hindered the side reactions of the electrode during charge and discharge, thereby prolonging the service life and safety performance of the electrode.

[0073] The chlorogenic acid modified collagen fibers and the mannan modified collagen fibers of Comparative Example 1 and Comparative Example 2 have a performance significantly worse than that of the examples, and the recovery effect of Comparative Example 1 is worse than that of Comparative Example 2. The main reason is that the crosslinking density of the collagen fibers modified by chlorogenic acid alone is low, and the skeleton structure is relatively loose, thereby affecting the size and morphology of the pore structure, and further leading to uneven distribution of nanocrystals, and a decline in the overall performance of the electrode. Comparative Example 3 does not fill nanocrystals, and the void structure of the material cannot be effectively filled and occupies additional volume, so that the high energy density advantage brought by the nanostructure cannot be fully utilized, the impedance of the electrode and electrolyte interface increases, the ion transmission resistance increases, and thus the capacity attenuation is fast. Comparative Example 4 does not use a nano-silver plating layer, and some uncontrollable side reactions occur on the surface of the electrode during the charging and discharging process, leading to electrode passivation, transition metal dissolution in the electrode, and changes in the structure, thereby affecting the use of the battery and shortening the service life of the battery. Long-term use has a safety hazard.

[0074] In summary, the use of a biological template to mediate the establishment of a three-dimensional skeleton for the electrode, filling of nanocrystals, and the use of a plating layer to protect the electrode can recycle and utilize waste lithium batteries, effectively rebuild the structure of the waste positive electrode material, restore its performance, and is green, environmentally friendly, energy-saving, and emission-reducing.

[0075] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as falling within the protection scope of the present application.

Claims

1. A method for structure reconstruction of spent lithium-ion battery cathode material assisted by multidimensional molecular engineering, characterized in that, The application relates to a method for preparing a lithium ion battery positive electrode plate. The method comprises the following steps: S1, dissolving chlorogenic acid and mannose in a first solvent, adding an acid solution and an initiator, and reacting to obtain chlorogenic acid-mannose; S2, dissolving the chlorogenic acid-mannose and collagen fibers in a second solvent, adding glutaraldehyde, and reacting to obtain chlorogenic acid-mannose modified collagen fibers; S3, dispersing the chlorogenic acid-mannose modified collagen fibers in a saturated sodium chloride solution, adding an acid solution and stirring for the first time, adding nano zirconium dioxide, and stirring for the second time to obtain chlorogenic acid-mannose modified collagen fibers filled with nano zirconium dioxide crystals; S4, mixing waste lithium ion battery positive electrode material powder and the chlorogenic acid-mannose modified collagen fibers filled with nano zirconium dioxide crystals, dispersing in a silver nitrate solution for silver plating to obtain a plated product; 2. The method according to claim 1, wherein, S5, mixing the plated product with a binder, and hot-pressing into a sheet to reconstruct a battery positive electrode sheet.

3. The method according to claim 1, wherein, In the step S1, the first solvent is any one or more of water, ethanol and dimethyl sulfoxide; the acid solution is any one or more of dilute sulfuric acid and dilute hydrochloric acid; and the initiator is any one or more of ammonium persulfate, azobisisobutyronitrile and dimethyl azobisisobutyrate.

4. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, characterized in that, In the step S1, the reaction temperature is 60-80 DEG C, and the reaction time is 4-6 h; and the mass ratio of the mannose, chlorogenic acid, initiator, acid solution and first solvent is 1:(1.6-2.6):(0.013-0.108):(0.05-0.1):(3-4).

5. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, characterized in that, In the step S2, the second solvent is an ionic liquid, which is any one or more of 1-butyl-3-methylimidazolium chloride ionic liquid, 1-allyl-3-methylimidazolium chloride ionic liquid and 1-ethyl-3-methylimidazolium chloride ionic liquid.

6. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, wherein, In the step S2, the concentration of the glutaraldehyde is 3-5 mol / L, and the adding amount is 2-5 mL; the reaction temperature is 40-50 DEG C, and the reaction time is 6-8 h; and the mass ratio of the collagen fibers, chlorogenic acid-mannose and second solvent is 1:(0.25-0.43):(2-3).

7. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, characterized in that, In the step S3, the first stirring time is 3-4 h; the second stirring time is 5-6 h, and the second stirring temperature is 40-50 DEG C; the acid solution is any one or more of dilute sulfuric acid and dilute hydrochloric acid; and the mass ratio of the chlorogenic acid-mannose modified collagen fiber powder, saturated sodium chloride solution, acid solution and nano zirconium dioxide is 1:(5-10):(0.05-0.1):(0.05-0.1). In the step S4, the concentration of the silver nitrate ethanol solution is 1-2 mol / L, and the amount is 30-40 mL.

8. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, wherein, In the step S4, the silver plating process is: mixing the waste positive material powder and the green acid-mannan modified collagen fiber filled with nano zirconium dioxide crystal, dispersing in silver nitrate solution, stirring at room temperature for 1-2 h, adding 10-15 g ascorbic acid, continuing to stir for 30-60 min, filtering, ethanol washing, vacuum calcining at 200-300 DEG C for 3-5 h.

9. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, wherein, In the step S5, the binder is any one or more of polyvinyl alcohol, polytetrafluoroethylene and polyvinylidene fluoride; and the mass ratio of the plated product to the adhesive is 1: (0.075-0.25).

10. The method for multi-dimensional molecular engineering assisted structural reconstruction of spent Li-ion battery cathode materials according to claim 1, wherein, In the step S5, the thermoforming process is: coating the aluminum foil coated with the positive electrode material with the plated product mixed with the adhesive, drying at 50-60°C, hot rolling at 130-180°C and 500-800 kg / cm 2 for 200-300 s under the conditions, and drying for 20-24 h.

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