Donor-acceptor polymer photocatalyst, preparation method and application thereof

Abstract

This invention belongs to the field of catalyst materials technology, specifically disclosing a class of donor-acceptor polymer photocatalysts, their preparation methods, and their applications in the recycling of spent lithium-ion batteries. This invention provides a class of donor-acceptor polymer photocatalysts, including D1-A-D1-D2 type polymer TFP and D-A1-D-A2 type polymer TSP. Polymer TFP / TSP is synthesized through a Schiff base reaction of 4,4'-(thiazolium[5,4-d]thiazolium-2,5-diyl)dibenzaldehyde with 2,7-diaminofluorene / 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide. Furthermore, polymer TSP can efficiently photocatalyze the synthesis of H2O2 in a water-benzyl alcohol system. The generated H2O2 enables the recovery of valuable heavy metals (Co, Li) from lithium-ion batteries at room temperature and pressure, providing an important safety guarantee for solving the "environmental pollution pain point" of spent batteries and the sustainable development of the new energy industry.

Description

Technical Field

[0001] This invention belongs to the field of photocatalyst technology, specifically relating to a class of donor-acceptor polymer photocatalysts and their preparation methods, as well as their application in the recycling of waste lithium-ion batteries. Background Technology

[0002] With the explosive growth of the global electric vehicle and large-scale energy storage industries, the market demand for lithium-ion batteries continues to rise, leading to an exponential increase in the generation of large quantities of waste lithium-ion batteries. Unrecycled waste batteries result in a serious waste of scarce metal resources such as cobalt and lithium, and environmental pollution. Currently, the market mainly uses hydrometallurgical methods to recover valuable metals from waste batteries; however, this method suffers from low metal recovery efficiency, high energy consumption, and secondary pollution.

[0003] Hydrogen peroxide (H2O2), as a green oxidizing leaching agent, offers significant advantages over traditional inorganic acids (sulfuric acid, hydrochloric acid) and strong oxidants (sodium chlorate, potassium dichromate) in the dissolution and recycling of waste lithium-ion battery electrode materials. These advantages include high efficiency, mildness, environmental friendliness, and low energy consumption. Photocatalytic H2O2 production, as a green and sustainable hydrogen peroxide preparation technology, directly utilizes solar energy to convert H2O and O2 into H2O2. It offers significant advantages such as mild reaction conditions, avoidance of storage and transportation risks, and low energy consumption, avoiding the high energy consumption and high pollution drawbacks of the traditional anthraquinone method, and has significant industrial application potential. Among these, donor-acceptor polymers, with their unique electronic structure and excellent photoelectrochemical properties, have the potential for highly efficient photocatalytic H2O2 production compared to traditional inorganic catalysts.

[0004] Therefore, developing a novel donor-acceptor polymer for efficient photocatalytic production of H2O2 is of great significance for the green and low-energy recycling of lithium-ion batteries. Summary of the Invention

[0005] To address the problems existing in the prior art, one objective of this invention is to provide a donor-acceptor polymer photocatalyst, specifically a D-A1-D-A2 type polymer TFP or a D1-A-D1-D2 type polymer TSP. This photocatalyst material possesses advantages such as a broad visible light response, high carrier separation efficiency, and excellent proton-electron coupling capability, enabling efficient H2O2 photosynthesis for green and low-energy recycling of waste batteries.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a donor-acceptor polymer photocatalyst, wherein the photocatalyst is a D1-A-D1-D2 type polymer TFP or a D-A1-D-A2 type polymer TSP, and the structural units of the polymer TFP and polymer TSP are respectively shown below: .

[0007] Further improvements to donor-acceptor polymer photocatalysts: Preferably, in the polymer TFP, the benzene ring acts as an electron donor and the thiazothiazole unit acts as an electron acceptor, thus having a unidirectional electron transport channel.

[0008] Preferably, the polymer TSP has superhydrophilic properties, wherein the benzene ring acts as an electron donor, thiazothiazole and benzothiophene-5,5-dioxide act as dual electron acceptors, and sulfone modification endows it with a bidirectional electron transport channel.

[0009] A second objective of this invention is to provide a method for preparing the above-mentioned donor-acceptor polymer photocatalyst, comprising the following steps: (1) Dissolve 1,4-o-phthalaldehyde and dithioacetamide in N,N-dimethylformamide and react upon heating to obtain 4,4'-(thiazole 5,4-d5,4- d Thiazole-2,5-dimethyl)dibenzaldehyde; (2) The product obtained in step (1) is dissolved in a mixed solvent of acetic acid, n-butanol and o-dichlorobenzene with 2,7-diaminofluorene or 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide, and after freezing-vacuuming-thawing in liquid nitrogen, a Schiff base reaction is carried out. (3) After the reaction is completed, the product is naturally cooled to room temperature, centrifuged and washed, then extracted by Soxhlet and freeze-dried under vacuum to obtain a hydrophilic donor-acceptor polymer.

[0010] Further improvements to the preparation method of donor-acceptor polymer photocatalysts: Preferably, the heating temperature in step (1) is 150 °C and the heating time is 5 h; the volume of the N,N-dimethylformamide solution is 30 mL, and the mass of 1,4-o-phenylenedialdehyde and dithioacetamide is 670 mg and 60 mg, respectively.

[0011] Preferably, the 4,4'-(thiazole 5,4-d5,4-) described in step (2) d Thiazole-2,5-dimethyl)dibenzaldehyde was 0.3 mmol, and 2,7-diaminofluorene or 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide was 0.45 mmol.

[0012] Preferably, in the mixed solvent of step (2), the concentration of acetic acid solution is 6 mol / L, and the volume ratio of acetic acid, n-butanol and o-dichlorobenzene is 0.3 mL:3 mL:3 mL.

[0013] Preferably, the Schiff base reaction in step (2) is carried out at 120 °C for 72 h.

[0014] The third objective of this invention is to provide an application of the above-mentioned donor-acceptor polymer photocatalyst in the photocatalytic preparation of hydrogen peroxide, comprising the following steps: S1. Photocatalytic preparation of hydrogen peroxide in a water-benzyl alcohol system; S2. The hydrogen peroxide solution generated by photocatalysis is mixed with LiCoO2, the cathode material of waste lithium-ion batteries, in glacial acetic acid solution and heated to react, so as to achieve the leaching and recovery of lithium and cobalt.

[0015] Further improvements to the application of the aforementioned donor-acceptor polymer photocatalyst in the photocatalytic preparation of hydrogen peroxide: Preferably, in step S1, the mass-to-volume ratio of photocatalyst to water and benzyl alcohol is (10-20 mg):(20-50 mL):(20-50 mL), the light source wavelength is ≥420 nm, the reaction temperature is 25℃, and the reaction time is 1-6 h; In step S2, the concentration of the glacial acetic acid solution is 0.3–1 mol / L. 50 mL of a solution containing hydrogen peroxide and 10–30 mg of waste lithium-ion battery cathode material LiCoO2 are added to 3–6 mL of the glacial acetic acid solution and mixed. The reaction temperature is 50–70 °C and the reaction time is 1–3 h.

[0016] The advantages of this invention compared to the prior art are as follows: (1) This invention provides a donor-acceptor polymer photocatalyst, which is a D1-A-D1-D2 type polymer TFP or a D-A1-D-A2 type polymer TSP; in the polymer TFP, the benzene ring acts as an electron donor and the thiazothiazole unit acts as an electron acceptor, and it has a unidirectional electron transport channel. The polymer TSP has superhydrophilic properties, wherein the benzene ring acts as an electron donor, and the thiazothiazole and benzothiophene-5,5-dioxide act as dual electron acceptors, and the sulfone group modification endows it with a bidirectional electron transport channel; therefore, the TSP has a wide visible light response, high carrier separation efficiency and excellent proton coupling electron capability.

[0017] (2) This invention provides a method for preparing a donor-acceptor polymer photocatalyst, wherein a D1-A-D1-D2 type polymer (TFP) is synthesized by a Schiff base reaction of 4,4'-(thiazolium[5,4-d]thiazolium-2,5-diyl)benzaldehyde and 2,7-diaminofluorene; or, a D-A1-D-A2 type polymer (TSP) is synthesized by a Schiff base reaction of 4,4'-(thiazolium[5,4-d]thiazolium-2,5-diyl)benzaldehyde and 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide. This type of photocatalyst exhibits excellent photocatalytic H2O2 production in a water-benzyl alcohol system. The generated H2O2 effectively leaches the positive electrode active material of lithium-ion batteries, representing a low-energy-consumption, environmentally friendly recycling technology without secondary pollution. Compared with other polymer catalysts, this polymer has advantages such as a wider visible light response, high carrier separation efficiency, and excellent proton-electron coupling ability. Attached Figure Description

[0018] Figure 1 This is a roadmap for the synthesis of the donor-acceptor polymer TFP in Example 1 and the synthesis of the donor-acceptor polymer TSP in Example 2.

[0019] Figure 2 It is the intermediate product TZ obtained in Example 1. 1 H liquid NMR image.

[0020] Figure 3 The images show the XRD patterns of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2.

[0021] Figure 4 Infrared spectra of the donor-acceptor polymer TFP prepared in Example 1, the donor-acceptor polymer TSP prepared in Example 2, the intermediate product TZ, and 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide (DS) and 2,7-diaminofluorene (DF).

[0022] Figure 5 The X-ray photoelectron spectra of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 are shown.

[0023] Figure 6 The UV-Vis absorption spectra are of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2.

[0024] Figure 7 The images show the water contact angles of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2.

[0025] Figure 8 The images show the surface electrostatic potential diagrams of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2.

[0026] Figure 9 Transient photocurrent diagrams of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2.

[0027] Figure 10 The graphs show the photocatalytic H2O2 production performance of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 in a water-benzyl alcohol system.

[0028] Figure 11 The donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 are used for the photocatalytic production of H2O2 on Li in LiCoO2. + and Co 2+ Dissolution rate chart.

[0029] Figure 12 The H2O2 generated by the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 under different concentrations of glacial acetic acid for 6 h of photoreaction has a positive effect on Li + and Co 2+ Dissolution rate chart. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing the D1-A-D1-D2 type polymer TFP. The synthetic route is as follows: Figure 1 As shown, it includes the following steps: S1. 1,4-o-phenylenedialdehyde (670 mg) and dithioacetamide (60 mg) were added to N,N-dimethylformamide solution (30 mL), heated at 150 °C for 5 h, the product was collected by filtration, and treated by chromatographic chromatography (petroleum ether / ethyl acetate = 3:1). After vacuum freeze-drying, 4,4'-(thiazolium[5,4-d]thiazolium-2,5-diyl)diphenylformaldehyde (TZ) was obtained. S2. 4,4'-(thiazolium[5,4-d]thiazolium-2,5-diyl)dibenzaldehyde (105 mg, 0.3 mmol) and 2,7-diaminofluorene (88 mg, 0.45 mmol) were added to a flask containing a mixed solvent, which was composed of glacial acetic acid (6 mol / L, 0.3 mL), n-butanol (3 mL) and o-dichlorobenzene (3 mL). The mixture was heated at 120 °C for 72 h under an argon atmosphere. The product was repeatedly washed by centrifugation with acetone, chloroform and anhydrous ethanol, and then freeze-dried under vacuum for 1 day to obtain the donor-acceptor polymer TFP.

[0033] Figure 2 The product corresponding to step S1 in Example 1 1 The H liquid NMR spectrum shows that the precursor TZ was successfully synthesized.

[0034] Example 2

[0035] This embodiment provides a method for preparing D-A1-D-A2 type polymer TSP. The synthetic route is as follows: Figure 1 As shown, it includes the following steps: S1, the same as step S1 in Example 1; S2. 4,4'-(thiazolium[5,4-d]thiazolium-2,5-diyl)dibenzaldehyde (105 mg, 0.3 mmol) and 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide (111 mg, 0.45 mmol) were added to a flask containing a mixed solvent, which was composed of glacial acetic acid (6 mol / L, 0.3 mL), n-butanol (3 mL), and o-dichlorobenzene (3 mL). The mixture was heated at 120 °C for 72 h under an argon atmosphere. The product was repeatedly washed by centrifugation with acetone, chloroform, and anhydrous ethanol, and then freeze-dried under vacuum for 1 day to obtain the donor-acceptor polymer TSP.

[0036] Figure 1 This is a route diagram for the synthesis of the donor-acceptor polymer TFP in Example 1 and the synthesis of the donor-acceptor polymer TSP in Example 2. Figure 1 As shown, intermediate TZ was first synthesized, and then polymer TFP was synthesized by reacting TZ with a Schiff base of 2,7-diaminofluorene. Polymer TSP was synthesized by reacting TZ with a Schiff base of 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide.

[0037] Figure 2 It is the intermediate product TZ obtained in Example 1. 1 The H liquid NMR spectrum confirmed the successful synthesis of TZ.

[0038] Figure 3The images show the XRD patterns of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2. Figure 3 It can be seen that the prepared TFP and TSP polymers have a certain degree of crystallinity.

[0039] Figure 4 Infrared spectra of the donor-acceptor polymer TFP prepared in Example 1, the donor-acceptor polymer TSP prepared in Example 2, the intermediate product TZ, and 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide (DS) and 2,7-diaminofluorene (DF). Figure 4 It can be seen that polymers TFP and TSP are at 1660 cm⁻¹ -1 The presence of a characteristic tensile vibration band of -C=N- indicates that the aldehyde group of 4,4'-(thiazole[5,4-d]thiazole-2,5-diyl)dibenzaldehyde and the amino group of 2,7-diaminofluorene or 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide underwent a dehydration polymerization reaction.

[0040] Figure 5 The X-ray photoelectron spectra of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 are shown. Figure 5 The formation of characteristic peaks (such as the binding energies of C=N and S=O bonds) proves that the polymers TFP and TSP have been successfully synthesized.

[0041] Figure 6 The images show the UV-Vis absorption spectra of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2. Figure 6 It is known that the donor-acceptor polymers TFP and TSP have excellent visible light absorption range and can make good use of visible light.

[0042] Figure 7 The water contact angle diagrams are for the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2. Figure 7 It is evident that the strongly electron-deficient polar sulfone group endows the polymer TSP with superhydrophilic properties, which is beneficial for enhancing the proton-electron coupling ability during the oxygen reduction reaction to produce H2O2.

[0043] Figure 8 The images show the surface electrostatic potential diagrams of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2. Figure 8 It is evident that the polymer TSP has a larger dipole moment (6.7D), resulting in a stronger built-in electric field within the molecule, which is beneficial for promoting the separation of photogenerated carriers.

[0044] Figure 9 Transient photocurrent plots of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2. Figure 9 This demonstrates that polymer TSP has a higher photocurrent density, which is beneficial for promoting the separation of photogenerated carriers.

[0045] Example 3

[0046] The donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 were used as photocatalysts for the recycling of spent lithium-ion batteries. S1. Take 20 mg of photocatalyst, 50 mL of water, and 20 mL of benzyl alcohol, mix them, and react them under a xenon lamp light source (light source wavelength ≥ 420 nm) at a temperature of 25℃ for 6 h to produce a solution containing hydrogen peroxide. S2. Take 50 ml of a solution containing hydrogen peroxide, add 30 mg of waste lithium-ion battery cathode material LiCoO2 and 5 mL of glacial acetic acid solution (concentration 0.6 mol / L), mix and stir, and heat in an oil bath at 70 ℃ for 3 h. The resulting suspension is filtered through a 0.22 μm needle filter to remove catalyst powder. After dilution to a certain proportion, the Li content in the solution is tested using ICP-OES. + and Co 2+ content.

[0047] The photocatalytic H2O2 production performance of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 in a water-benzyl alcohol system was evaluated, and the results are as follows: Figure 10 As shown, the photocatalytic H2O2 production efficiencies of TFP and TSP are 31140 μmol / g / h and 69650 μmol / g / h, respectively.

[0048] The donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 were evaluated for photocatalytic production of H2O2 and its application in dissolving LiCoO2. The results are as follows: Figure 11 As shown. By Figure 11 It can be seen that after 6 h of photocatalytic reaction, the H2O2 produced by TSP dissolved 13.7 μmol and 12.1 μmol of Li and Co metals, respectively; the H2O2 produced by TFP dissolved 7.1 μmol and 6.5 μmol of Li and Co metals, respectively.

[0049] Example 4

[0050] The donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 were used as photocatalysts for the recycling of waste lithium-ion batteries. The specific steps were the same as in Example 3, except that the concentrations of glacial acetic acid were 0.3 mol / L, 0.5 mol / L and 0.9 mol / L, respectively.

[0051] The performance of the donor-acceptor polymer TFP prepared in Example 1 and the donor-acceptor polymer TSP prepared in Example 2 in photocatalytic H2O2 production and recycling of spent lithium-ion batteries under different concentrations of glacial acetic acid was evaluated. The results are as follows: Figure 12 As shown. By Figure 12 It can be seen that the H2O2 generated by the polymer TSP after 6 h of photoreaction has the highest dissolution amount of Li and Co metals in 0.5 mol / L glacial acetic acid solution, reaching 15.5 μmol and 14.2 μmol, respectively.

[0052] The D-A1-D-A2 type polymer (TSP) designed and synthesized in this invention possesses advantages such as a wide visible light response, high carrier separation efficiency, and excellent proton-electron coupling ability, thereby enabling efficient photocatalytic synthesis of H2O2. The photocatalytically generated H2O2 effectively leaches LiCoO2, the cathode material of lithium-ion batteries, representing a low-energy-consumption, pollution-free, and environmentally friendly recycling method. In summary, the polymer TSP has the practical application potential for photocatalytic H2O2 production in lithium-ion battery recycling.

[0053] The foregoing description of the embodiments is intended to facilitate understanding and application of the present invention by those skilled in the art. Those skilled in the art can easily make various adjustments to these embodiments (including the synthesis processes of TSP and TFP), such as adjusting the ratio and amount of the reaction solvent, changing the type or proportion of the reaction ligands, and altering the reaction time and temperature. Furthermore, the general principles described herein can be directly applied to other embodiments without any inventive effort. Therefore, the scope of protection of the present invention is not limited to the foregoing embodiments. Improvements and modifications made by those skilled in the art based on the content disclosed in this invention, without departing from the core scope of the present invention, should all be included within the scope of protection of this invention.

Claims

1. A class of donor-acceptor polymer photocatalysts, characterized in that, The photocatalyst is a D1-A-D1-D2 type polymer TFP or a D-A1-D-A2 type polymer TSP, and the structural units of the polymer TFP and polymer TSP are shown below: 。 2. The donor-acceptor polymer photocatalyst according to claim 1, characterized in that, In the polymer TFP, the benzene ring acts as an electron donor and the thiazothiazole unit acts as an electron acceptor, forming a unidirectional electron transport channel.

3. The donor-acceptor polymer photocatalyst according to claim 1, characterized in that, The polymer TSP has superhydrophilic properties, wherein the benzene ring acts as an electron donor, thiazothiazole and benzothiophene-5,5-dioxide act as dual electron acceptors, and sulfone modification endows it with a bidirectional electron transport channel.

4. A method for preparing a donor-acceptor polymer photocatalyst according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Dissolve 1,4-o-phthalaldehyde and dithioacetamide in N,N-dimethylformamide and react upon heating to obtain 4,4'-(thiazole 5,4-d5,4- d Thiazole-2,5-dimethyl)dibenzaldehyde; (2) The product obtained in step (1) is dissolved in a mixed solvent of acetic acid, n-butanol and o-dichlorobenzene with 2,7-diaminofluorene or 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide, and after freezing-vacuuming-thawing in liquid nitrogen, a Schiff base reaction is carried out. (3) After the reaction is completed, the product is naturally cooled to room temperature, centrifuged and washed, then extracted by Soxhlet and freeze-dried under vacuum to obtain a hydrophilic donor-acceptor polymer.

5. The method for preparing the donor-acceptor polymer photocatalyst according to claim 4, characterized in that, The heating temperature in step (1) is 150℃ and the heating time is 5 h; the volume of the N,N-dimethylformamide solution is 30 mL, and the mass of 1,4-o-phenylenedialdehyde and dithioacetamide is 670 mg and 60 mg, respectively.

6. The method for preparing the donor-acceptor polymer photocatalyst according to claim 4, characterized in that, The 4,4'-(thiazole 5,4-d5,4-) mentioned in step (2) d Thiazole-2,5-dimethyl)dibenzaldehyde was 0.3 mmol, and 2,7-diaminofluorene or 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide was 0.45 mmol.

7. The method for preparing the donor-acceptor polymer photocatalyst according to claim 4 or 6, characterized in that, In the mixed solvent of step (2), the concentration of acetic acid solution is 6 mol / L, and the volume ratio of acetic acid, n-butanol and o-dichlorobenzene is 0.3 mL:3 mL:3 mL.

8. The method for preparing the donor-acceptor polymer photocatalyst according to claim 4, characterized in that, The Schiff base reaction described in step (2) was carried out at 120 °C for 72 h.

9. The application of a donor-acceptor polymer photocatalyst according to any one of claims 1-3 in the recycling of spent lithium-ion batteries, characterized in that, Includes the following steps: S1. Photocatalytic preparation of hydrogen peroxide in a water-benzyl alcohol system; S2. The hydrogen peroxide solution generated by photocatalysis is mixed with LiCoO2, the cathode material of waste lithium-ion batteries, in glacial acetic acid solution and heated to react, so as to achieve the leaching and recovery of lithium and cobalt.

10. The application of the donor-acceptor polymer photocatalyst according to claim 9 in the recycling of spent lithium-ion batteries, characterized in that, In step S1, the mass-to-volume ratio of photocatalyst to water and benzyl alcohol is (10-20 mg):(20-50 mL):(20-50 mL), the light source wavelength is ≥420 nm, the reaction temperature is 25℃, and the reaction time is 1-6 h. In step S2, the concentration of the glacial acetic acid solution is 0.3–1 mol / L. 50 mL of a solution containing hydrogen peroxide and 10–30 mg of waste lithium-ion battery cathode material LiCoO2 are added to 3–6 mL of the glacial acetic acid solution and mixed. The reaction temperature is 50–70℃ and the reaction time is 1–3 h.

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