Solar energy driven lithium ion battery cathode material string recovery system and method

Abstract

The application relates to a solar-driven lithium ion battery positive electrode material series connection recovery system and method, which comprises flat plate type photocatalytic units, extraction units, acidification units and solid bed type electrode recovery units connected in series. Under irradiation, the front-stage photocatalytic units continuously and efficiently generate hydrogen peroxide, which is continuously introduced into the rear-stage electrode recovery units after online extraction dilution and acidification treatment. The hydrogen peroxide is used to induce oxidation or reduction reaction of electrode metal ions, and the continuous and stable leaching of metal ions is realized with the aid of an acid medium. Finally, high-value metal ions are recovered through chemical precipitation. Compared with traditional kettle type reaction devices and intermittent operation modes, the above-mentioned series connection flow recovery system can significantly improve the utilization rate of hydrogen peroxide, realize the efficient, continuous and stable leaching of metal ions, effectively improve the overall recovery efficiency of the system, and has good large-scale application prospect.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery recycling technology, specifically to a solar-driven series recycling system and method for lithium-ion battery cathode materials. Background Technology

[0002] Hydrometallurgy is currently the core process for recycling cathode materials in lithium-ion batteries, characterized by mild reaction conditions and high recovery rates. This process typically utilizes a batch reactor to achieve the reductive leaching of transition metal species through the synergistic effect of an acidic medium and a reducing agent (such as H₂O₂). However, traditional batch reactors have the following drawbacks in practical operation: (1) Severe catalytic decomposition and ineffective loss of reducing agent: As the leaching reaction progresses, the concentration of transition metal ions in the liquid phase continuously increases. These leached transition metal ions have a strong catalytic decomposition effect on H2O2, causing the concentration of H2O2 in the reaction system to decrease exponentially. In order to maintain the necessary reaction rate, the process requires excessive addition and replenishment of H2O2, which not only significantly increases the cost of chemical reagents but also causes serious waste of resources.

[0003] (2) The inherent heat-driven mode leads to high process energy consumption: Traditional batch reactor processes rely entirely on external heating to provide the activation energy required for the reaction. During large-scale industrial scale-up, maintaining the overall high-temperature environment of the reactor requires a large amount of heat energy, which leads to a further increase in recovery costs and carbon emissions.

[0004] (3) The intermittent operation mode limits the overall recovery efficiency: The batch reactor adopts a single-batch intermittent mode of feeding-reaction-discharging. In this reaction system, metal ions continue to accumulate in the liquid phase, which in turn further accelerates the decomposition of H2O2, making it difficult to further improve the degradation efficiency of the cathode material. At the same time, the frequent manual switching between batches and repeated heating processes also significantly increase the time cost and energy consumption per unit of production.

[0005] To address the aforementioned issues, the inventors previously explored a method for recycling cathode materials from light-driven lithium-ion batteries (Patent No.: ZL202510859017.0). This research designed and synthesized a stable benzobisthiazole-linked polymer photocatalyst capable of efficiently generating H2O2 in situ under visible light, and synergistically with acetic acid to achieve metal leaching under mild conditions. This method utilizes light energy to achieve in-situ H2O2 production and system heating, effectively reducing the energy consumption of the reaction system. However, this system still cannot meet the requirements for continuous recycling, and its recycling capacity is limited. In addition, the cost of the polymer photocatalyst used is relatively high, raising the threshold for large-scale application. Furthermore, the limited adjustment space of the reaction parameters restricts the effective implementation of subsequent performance optimization work, further limiting the practical application potential of this recycling technology.

[0006] Therefore, developing a novel cathode material recycling system that combines low energy consumption and continuous operation is of great scientific significance and industrial application value for breaking through the technical bottlenecks of traditional wet recycling and existing light-driven recycling, and promoting the green and large-scale recycling of waste lithium batteries. Summary of the Invention

[0007] To address the technical problems of low reducing agent utilization, high energy consumption, and lack of continuous processing in existing lithium-ion battery cathode material recycling technologies, this invention provides a solar-driven lithium-ion battery cathode material series recycling system and method. This system can achieve efficient and continuous recycling of high-value metal elements in cathode materials under low energy consumption conditions and has significant potential for large-scale application.

[0008] Specifically, the following technical solutions are provided: The first aspect of this invention provides a solar-driven lithium-ion battery cathode material series recovery system, comprising a planar photocatalytic unit, an extraction unit, an acidification unit, and a solid-bed electrode recovery unit connected in series, wherein... The flat-plate photocatalytic unit is provided with an oil phase inlet, a gas phase inlet, and a reaction liquid outlet. It is used to allow the oil phase containing the photocatalyst to form a continuous gas-liquid two-phase flow with the oxygen-containing gas and carry out a photocatalytic reaction to generate H2O2. After the reaction, the oil phase is sent to the extraction unit through the reaction liquid outlet. The extraction unit is equipped with a reaction liquid inlet, a pure water inlet, and an H2O2 aqueous solution outlet connected to the reaction liquid outlet. It is used to introduce pure water to extract H2O2 from the oil phase after the reaction into the aqueous phase, and to control the concentration of the obtained H2O2 aqueous solution by adjusting the pure water flow rate. The resulting H2O2 aqueous solution with the target concentration is sent to the acidification unit through the H2O2 aqueous solution outlet. The acidification unit is equipped with an H2O2 aqueous solution inlet, an acid solution inlet, and an acidic H2O2 aqueous solution outlet connected to the H2O2 aqueous solution outlet. It is used to introduce an acid solution to mix with the H2O2 aqueous solution, and to control the acid concentration of the resulting acidic H2O2 aqueous solution by adjusting the concentration or flow rate of the acid solution. The resulting acidic H2O2 aqueous solution with the target acid concentration is sent to the solid bed electrode recovery unit through the acidic H2O2 aqueous solution outlet. The solid-bed electrode recovery unit is equipped with an acidic H2O2 aqueous solution inlet, a feeding port, and a leachate outlet connected to the acidic H2O2 aqueous solution outlet. It is used to flush the cathode material to be recovered with a continuously flowing acidic H2O2 aqueous solution to leach out metal ions. The resulting leachate containing metal ions flows out through the leachate outlet and is collected.

[0009] In the series recovery system constructed by the present invention, the photocatalytic reaction system consists of a continuous gas-liquid two-phase flow composed of an oil phase containing a catalyst and oxygen (or air). This continuous gas-liquid flow continuously passes through a flat-plate reaction device for continuous reaction. During the photocatalytic reaction, the oxygen in the gas phase provides a sufficient oxygen source to maintain high-efficiency H2O2 production, which dissolves in the oil phase. The H2O2-rich oil phase then continuously enters the extraction unit, where H2O2 is extracted into the aqueous phase using continuously introduced pure water. During this process, an aqueous H2O2 solution with a specific concentration can be precisely obtained by adjusting the water volume. Subsequently, the H2O2 aqueous solution is simultaneously introduced into the acidification unit with an acid solution of a set concentration for mixing. By adjusting the inflow rate of the acid solution, the acid concentration in the final acidic H2O2 aqueous solution can be controlled online as needed. Finally, the prepared acidic H2O2 aqueous solution is continuously fed into the solid-bed electrode recovery unit at a constant flow rate for continuous leaching and recovery of the electrode material.

[0010] Furthermore, the planar photocatalytic unit includes a planar photocatalytic device, which is assembled by a tube passing through pre-drilled holes in a support plate. The gas-liquid two-phase continuous flow enters the planar photocatalytic device through the tube to carry out the photocatalytic reaction. Preferably, the pore diameter of the channel is 1-2 mm larger than the outer diameter of the tube to facilitate the insertion of the tube.

[0011] In this invention, the photocatalytic device is configured with a planar structure to increase the effective light-receiving area of ​​the photocatalytic reaction, improve the solar energy capture efficiency, and facilitate the parallel or series connection of multiple units to enhance the large-scale production capacity of H2O2. Compared with traditional batch reactors, the planar structure has the advantages of a shorter light path, more uniform light reception, and less light attenuation, which is conducive to the full excitation of the photocatalyst under illumination, thereby achieving efficient and continuous generation of H2O2 and providing a stable concentration and controllable flow rate of H2O2 aqueous solution for the downstream recovery unit.

[0012] Furthermore, the rigid tubing is made of polytetrafluoroethylene, and the support plate is made of one or more of polyethylene, polyvinyl chloride, polypropylene, and polymethyl methacrylate.

[0013] Furthermore, the support plate has a first side and a second side, and the first side and the second side are respectively provided with multiple layers of staggered channels. The pipes are inserted into the channels and arranged tightly through the holes of the channels to form a multi-layer pipe arrangement structure.

[0014] In some preferred embodiments, the support plate has three layers of staggered channels on its first and second sides, and the left-right spacing L between adjacent channels in the same layer is 20-30 mm, and the spacing H between two adjacent layers of channels is 10-20 mm.

[0015] In this invention, a multi-layered pipe arrangement structure is set on the support plate. On the one hand, it can integrate more reaction pipes in a limited space, significantly increasing the photocatalytic reaction interface per unit volume and improving the overall yield of H2O2. On the other hand, the multi-layered staggered arrangement ensures that each pipe is evenly distributed and does not block each other, ensuring that each pipe can receive sufficient light, while improving the interlayer fluid redistribution and mass transfer effect, avoiding uneven reaction. In addition, the pipes are inserted and assembled through pre-reserved gaps in the channels, which facilitates installation and disassembly and reduces maintenance costs. Furthermore, by further rationally setting the interlayer spacing and channel spacing, this invention ensures light transmittance while achieving a tight arrangement of pipes, ensuring uniform flow distribution in each pipe and maintaining a long-term stable output of H2O2 concentration at the outlet.

[0016] Furthermore, the solid-bed electrode recovery unit includes one or more tubular reaction devices arranged in parallel. Each tubular reaction device is provided with a feed port, an acidic H2O2 aqueous solution inlet, and a leachate outlet. The feed port is used to feed the cathode material to be recovered into the tubular reaction device.

[0017] Furthermore, the extraction unit is also provided with an oil phase outlet to discharge the lower layer of oil after extraction or to transport it through a pipeline to a storage device that provides the oil phase.

[0018] Furthermore, a heating device is provided around the tubular reaction device to regulate the temperature of the tubular reaction device. The heating device may be a circulating heating medium jacket or a photothermal heating device based on Fresnel lens light collection.

[0019] In some preferred embodiments, the tubular reaction device is a glass tube, and an outer glass tube is fitted around the outside of the tubular reaction device. The annular gap between the outer glass tube and the tubular reaction device forms a heating medium circulation jacket. The outer glass tube is provided with a heating medium inlet and a heating medium outlet.

[0020] Furthermore, a porous plate is provided at the leaching outlet of the tubular reaction device to stabilize and support the electrode material while facilitating the outflow of the leaching solution; at least one layer of porous filter membrane is laid on the surface of the porous plate away from the leaching outlet to prevent the positive electrode material inside the tube from being lost with the leaching solution.

[0021] In some preferred embodiments, the porous plate is a porous glass plate, and the porous filter membrane is made of one or more of glass fiber, cellulose and nonwoven fabric. The porous filter membrane has a pore size of 1-2 μm and a thickness of 1-3 mm, more preferably a porous filter membrane with a pore size of 1.1-1.3 μm and a thickness of 1.1-1.5 mm, which has good water permeability and stability, and also has good positive electrode material cutoff performance.

[0022] Furthermore, the tubular reaction device is inclined as a whole, and the inlet end of the acidic H2O2 aqueous solution of the tubular reaction device is higher than the outlet end of the leachate, with an inclination angle of 0-90°, preferably 10°-30°.

[0023] In this invention, the tubular reaction device is preferably set at an angle. On the one hand, the acidic H2O2 aqueous solution continuously introduced from the front end flows continuously through the positive electrode material inside the tube from the high inlet end to the low outlet end under the action of gravity. The flow reaction mode realizes the rapid leaching of metal ions. At the same time, the leached metal ions are promptly removed from the recovery unit with the liquid flow, effectively avoiding their residence and accumulation in the bed. This significantly reduces the catalytic decomposition loss of H2O2 by transition metal ions, ensuring the efficient utilization of H2O2 and the long-term stable leaching of metal ions. Meanwhile, the reaction liquid flows through the recovery tube by gravity, eliminating the need for an additional conveying power device, simplifying the system structure and reducing operating energy.

[0024] A second aspect of the present invention also provides a method for recycling lithium-ion battery cathode materials using the system described in the first aspect, comprising the following steps: S1. The oil phase containing the photocatalyst is mixed with oxygen-containing gas to form a continuous gas-liquid two-phase flow, which is then introduced into a flat-plate photocatalytic unit to carry out a photocatalytic reaction and generate an oil phase containing H2O2. S2. The oil phase containing H2O2 is continuously passed into the extraction unit, pure water is introduced to extract H2O2 into the aqueous phase, and an aqueous solution with the target concentration of H2O2 is obtained by adjusting the addition rate of pure water. S3. The H2O2 aqueous solution and the acid solution are simultaneously introduced into the acidification unit for mixing, and an acidic H2O2 aqueous solution with the target acid concentration is obtained by adjusting the concentration or flow rate of the acid solution. S4. The acidic H2O2 aqueous solution is continuously passed into the solid-bed electrode recovery unit, so that it flows through the cathode material to be recovered placed in the solid-bed electrode recovery unit, continuously flushing and leaching metal ions from the cathode material, and collecting the leachate containing metal ions.

[0025] Further, in step S1, the oil phase comprises a non-water-soluble alcohol and / or an amine reagent, such as a pure non-water-soluble alcohol or amine reagent or its cyclohexane solution. The non-water-soluble alcohol is selected from one or more of n-pentanol, isopentanol, n-hexanol, isohexanol, 2-ethylhexanol, n-octanol, isooctanol, n-decanol, isodecanol and benzyl alcohol. The amine reagent is selected from one or more of aromatic benzylamine derivatives and tetrahydroisoquinoline derivatives.

[0026] In some preferred embodiments, benzyl alcohol is used as the oil phase, resulting in better H2O2 production rate and photocatalyst stability.

[0027] Further, in step S1, the concentration of the photocatalyst in the oil phase is 0.1-3 g / L, preferably 0.2-0.5 g / L; the photocatalyst can be selected from commercially available or synthetic small molecule photocatalysts or polymer photocatalysts, such as one or more selected from perylene imide derivatives, anthraquinone and its derivatives, fluorene ketone and its derivatives, and polymer photocatalysts (e.g., porous polymer materials).

[0028] In some preferred embodiments, the photocatalyst is selected from one of the compounds shown in the following structures: DTAQ is preferred.

[0029] Further, in step S1, the flow rate ratio of the oil phase to the oxygen-containing gas is (0.3-1.2):1, preferably (0.5-0.8):1.

[0030] Furthermore, in step S1, the photocatalytic reaction is carried out under sunlight or artificial light, with a light intensity of 50-500 mW. cm -2 Preferably 80-200 mW cm -2 .

[0031] Further, in step S2, the rate at which pure water is added to the extraction unit for extracting H2O2 is 1-10 mL / min, preferably 6-7.5 mL / min; the concentration of the H2O2 aqueous solution is 10-300 mM, preferably 40-50 mM.

[0032] Further, in step S3, the acid addition rate in the acidification unit is 0.1-2 mL / min, preferably 0.3-0.5 mL / min; the acid concentration in the acidic H2O2 aqueous solution is 0.1-4 M, preferably 0.5-1 M; the acid in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, ascorbic acid, formic acid, acetic acid, propionic acid, and oxalic acid.

[0033] Further, in step S4, the cathode material to be recycled is selected from LiCoO2, LiFePO4, and LiCo. x Ni y Mn 1-x- y One or more of O2, LiMn2O4, and black powder (containing a mixture of cathode materials, organic binders, and additives) obtained from dismantling lithium-ion battery cathode sheets, wherein 0 <x,0<y,x+y<1。

[0034] Further, in step S4, the flow rate of the acidic H2O2 aqueous solution into the solid-bed electrode recovery unit is 1-3 mL / min, preferably 1.3-1.6 mL / min.

[0035] Furthermore, in step S4, the temperature of the solid-state bed electrode recovery unit is 50-90 ℃, for example, 80 ℃.

[0036] The present invention has the following beneficial effects: The series-connected recovery system provided by this invention integrates photocatalytic H2O2 production with the wet recovery process of lithium-ion battery cathode materials into a continuous flow system. This is achieved by sequentially coupling a photocatalytic unit, an extraction unit, an acidification unit, and a solid-bed electrode recovery unit in series to form a continuous flow reaction system. Specifically, the photocatalytic unit utilizes solar energy to generate H2O2 in situ, which is then directly introduced into the subsequent solid-bed recovery unit after online extraction, dilution, and acidification. The extraction and acidification units can independently control the H2O2 and acid concentrations as needed, offering flexible and convenient operation. The entire system abandons the intermittent operation mode of traditional batch reactors, featuring a compact structure and high integration, providing a reliable hardware foundation for continuous recovery processing.

[0037] The recovery method provided by this invention utilizes a series flow reaction mode, where a continuously generated acidic H2O2 aqueous solution flows continuously through a solid-bed recovery unit filled with cathode material, continuously flushing the cathode material. The leached transition metal ions flow out with the solution in real time, effectively preventing the retention and accumulation of metal ions in the recovery unit. This significantly reduces the catalytic decomposition loss of H2O2 by transition metal ions, ensuring efficient utilization of H2O2 and long-term stable leaching of metal ions. Simultaneously, the electrode material to be recovered can be replenished at any time through the feed port, solving the problem of continuous feeding in traditional processes and greatly improving the electrode processing efficiency per unit time. Both the photocatalytic unit and the electrode recovery unit can directly utilize solar energy as the main energy input, eliminating the need for external heating devices and significantly reducing process energy consumption and operating costs.

[0038] Compared to traditional wet recycling technologies, this invention avoids time-consuming intermittent separation operations, meeting the practical industrial needs for uninterrupted system operation and showing promising prospects for large-scale application. This method not only significantly improves the utilization rate of reducing agents and the leaching efficiency of metal ions, but also substantially reduces the cost of chemical reagents and energy consumption. It provides a practical and feasible technical path for the large-scale green recycling of waste lithium-ion battery cathode materials, and has significant practical value for promoting the sustainable development of the new energy industry. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the series recycling system for the light-driven recovery of lithium-ion battery cathode materials provided by the present invention.

[0040] Figure 2 Design drawings for plastic panels (left); Schematic diagram of pipeline routing (right).

[0041] Figure 3 This is a schematic diagram of the tubular reaction device in the solid bed electrode recovery unit.

[0042] Figure 4 The graph shows a comparison of the production efficiency of H2O2 using different photocatalysts in Examples 1 and 2.

[0043] Figure 5 The figure shows the experimental results of H2O2 produced by the photocatalytic end degrading LiCoO2 in Example 1.

[0044] Figure 6 For Examples 3-7, Li₂ produced by photocatalytic H₂O₂ degrades LiCoO₂ for one hour, from which Li₂ dissolves. + Co 2+ A graph comparing concentration and amount of substance.

[0045] Figure 7 For Examples 8-12, Li₂ produced by photocatalytic H₂O₂ degrades LiCoO₂ for one hour, from which Li₂ dissolves. + Co 2+ A graph comparing concentration and amount of substance.

[0046] Figure 8 For Examples 1, 13, and 14, Li₂ produced by photocatalysis degrades LiCoO₂, and one hour later, Li₂ dissolves from LiCoO₂. + Co 2+ A graph comparing concentration and amount of substance.

[0047] Figure 9 For Comparative Examples 1-6, Li₂ dissolved from LiCoO₂ was degraded by H₂O₂ produced by photocatalysis one hour later. + Co 2+ A graph comparing concentration and amount of substance.

[0048] Figure 10 The Li dissolved from LiCoO2 after one hour of operation in a continuous flow reactor (left) in Example 1 and one hour of operation in a batch reactor (right) in Comparative Example 7 are compared. + Co 2+ A graph comparing concentration and amount of substance.

[0049] Figure 11 This is a schematic diagram of the actual device during outdoor operation.

[0050] Figure 12The graph shows the H2O2 production efficiency results obtained from outdoor experiments.

[0051] Figure 13 The graph shows the results of metal leaching efficiency measured in an outdoor LiCoO2 recovery experiment. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms “comprising” or “including” used in this invention may also be replaced with the closed form “is” or “consisting of”.

[0054] The raw materials used in the following examples are all commercially available or prepared by methods known in the art, and all performance tests are conducted using standardized methods to ensure data comparability and reliability.

[0055] like Figure 1 As shown, the tandem recovery system constructed in this invention consists of a flat continuous flow photocatalytic unit, an extraction unit, an acidification unit, and a solid bed electrode recovery unit connected in series.

[0056] In the photocatalytic unit, the reaction system consists of a continuous gas-liquid two-phase flow of an oil phase containing the catalyst and oxygen (or air), which is mixed via a T-valve and then enters a flat-plate reactor. Under illumination, the oxygen in the gas phase provides a sufficient oxygen source, generating H2O2 in situ via photocatalysis and dissolving it in the oil phase. The H2O2-rich oil phase flows out continuously after the reaction and enters the extraction unit. Simultaneously, external pure water flows continuously into the extraction unit at a set flow rate, fully extracting the H2O2 from the oil phase into the aqueous phase. By adjusting the pure water feed rate, a specific concentration of H2O2 aqueous solution can be precisely obtained. The lower oil phase after extraction is transported through an oil phase outlet located at the bottom of the extraction unit to an oil phase storage device for supplying the oil phase, entering the next reaction cycle. The resulting upper H2O2 aqueous solution is simultaneously introduced into the acidification unit along with an acid solution. By adjusting the inflow rate of the acid solution, the acid concentration in the final acidic H2O2 aqueous solution can be controlled online as needed. The prepared acidic H2O2 aqueous solution is continuously pumped into the solid bed electrode recovery unit at a constant flow rate to continuously scour and leach the positive electrode material. The leachate flows out through the porous filter membrane at the end of the device and enters the collection unit. The obtained metal ions are recovered by a stepwise chemical precipitation method.

[0057] like Figure 2As shown, the planar continuous flow photocatalytic unit is mainly assembled from a supporting plastic plate and PTFE rigid tubes inserted therethrough. Multiple layers of staggered channels are formed on opposite sides of the plastic plate. The PTFE rigid tubes are inserted into these channels and tightly arranged through the holes, forming a multi-layered pipe arrangement structure. To ensure a tight pipe arrangement while facilitating the smooth insertion of the PTFE rigid tubes, the diameter of the channels is 1-2 mm larger than the outer diameter of the PTFE rigid tubes. In this embodiment, three layers of staggered channels (upper, middle, and lower) are formed on both sides of the plastic plate. The horizontal spacing between adjacent channels in the same layer is 20-30 mm, and the spacing between two adjacent layers of channels is 10-20 mm, thus constructing a high-density tube bundle network to ensure uniform light exposure and stable flow of the reaction liquid in each channel. The plastic plate is made of one or more of polyethylene, polyvinyl chloride, polypropylene, and polymethyl methacrylate.

[0058] like Figure 3 As shown, the solid-bed electrode recovery unit adopts a tubular structure, with an adapter connected to its front end. The adapter is equipped with an inlet for an acidic H2O2 aqueous solution and an electrode material feeding port. The positive electrode material to be recovered is fed into the tube through the feeding port, and the acidic H2O2 aqueous solution is introduced through the inlet. A porous glass plate (porous glass frosted plate) is provided at its rear end to support and fix the electrode material and ensure the smooth outflow of the leachate. A porous filter membrane is laid on the surface of the porous glass plate to prevent the electrode material from being lost with the liquid flow. The filter membrane material is selected from glass fiber, cellulose, and non-woven fabric, with a pore size of 1-2 μm and a thickness of 1-3 mm. A heating medium circulation sleeve is provided outside the glass tube (heating can be achieved by circulating water jacket heating or photothermal effect heating based on Fresnel lens focusing) to provide the temperature required for the reaction. Furthermore, the inlet of the acidic H2O2 aqueous solution in the solid-bed electrode recovery unit is higher than the outlet of the leachate, and the entire unit is inclined at an angle of 0-90° (preferably 10°-30°). This ensures smooth liquid flow and prevents material blockage, while allowing the acidic H2O2 aqueous solution introduced at the front end to continuously flow through the cathode material-filled bed under gravity. This enhances the interfacial mass transfer between the solution and the cathode material, significantly accelerating the dissolution and recovery efficiency of metal ions. To improve the electrode processing capacity per unit time, the solid-bed electrode recovery unit can be arranged in a parallel configuration.

[0059] Example 1 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system, wherein the series recycling system is as follows: Figure 1 As shown, the specific steps include: Oil phase preparation: Dissolve the photocatalyst DTAQ (620 mg) in benzyl alcohol (200 mL) and ultrasonically disperse for 10 minutes to form a homogeneous solution.

[0060] In the photocatalytic unit, oil and oxygen are mixed and introduced into the flat-plate photocatalytic device through a T-valve at flow rates of 8 mL / min and 16 mL / min, respectively, and irradiated using simulated sunlight (wavelength greater than 420 nm, light intensity 100 mW cm⁻¹). -2 Secondly, the reacted oil phase and external pure water (7.5 mL / min) are simultaneously introduced into the extraction unit to fully extract H2O2 from the oil phase into the aqueous phase. The resulting upper H2O2 aqueous solution (concentration approximately 50 mM) enters the acidification unit, while the lower oil phase is recovered and enters the next reaction cycle. At the acidification unit, glacial acetic acid (pure acetic acid) is introduced into the H2O2 aqueous solution at a certain flow rate (0.5 mL / min) to obtain an H2O2 aqueous solution containing 1 M acetic acid. Finally, the acidified H2O2 aqueous solution is introduced into a solid bed recovery unit filled with waste electrode material at a flow rate of 1.3 mL / min. The recovery device is tilted at 12°, and LiCoO2 is selected as the electrode material. The initial feed is 800 mg, followed by 400 mg added every hour. The circulating water temperature is maintained at 80°C. Metal ions gradually leach from the positive electrode material and continuously flow out from the outlet to obtain a Li-containing solution. + With Co 2+ The leachate.

[0061] Example 2 A method for recycling lithium-ion battery cathode materials using a solar-powered lithium-ion battery cathode material series recycling system differs from Example 1 only in that the oil phase is different. The specific oil phase preparation in this example is as follows: The photocatalyst HAPDI (500 mg) was dissolved in benzyl alcohol (200 mL) and ultrasonically dispersed for 10 minutes to form a homogeneous solution.

[0062] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0063] The H2O2 production efficiency of this embodiment is similar to that of Embodiment 1. Figure 4 As shown, the DTAQ photocatalytic H2O2 production performance remained stable within 5 hours, with a yield of 29.8 mmol / h. -1 The H2O2 concentration remained stable at approximately 67 mM; the H2O2 yield of HAPDI was approximately 4.3 mmol / h. -1 The H2O2 concentration remained at around 20 mM after 2 hours.

[0064] Example 3 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: (1) In the extraction unit, external pure water is continuously introduced at a rate of 37.5 mL / min. After extraction, the concentration of the upper H2O2 aqueous solution is about 10 mM. (2) In the acidification unit, an aqueous solution of H2O2 containing 0.2 M acetic acid is obtained; The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0065] Example 4 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: (1) In the extraction unit, the flow rate of pure water is 18.8 mL / min, and after extraction, the concentration of the upper H2O2 aqueous solution is 20 mM. (2) In the acidification unit, glacial acetic acid is continuously introduced at a rate of 0.3 mL / min to obtain an aqueous solution of H2O2 containing 0.2 M acetic acid; The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0066] Example 5 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is continuously introduced at a rate of 0.1 mL / min to obtain an aqueous solution of H2O2 containing 0.2 M acetic acid; The remaining operations were the same as in Example 1 (the concentration of the upper H2O2 aqueous solution was 50 mM), yielding Li-containing... + With Co 2+ The leachate.

[0067] Example 6 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: (1) In the extraction unit, the flow rate of pure water is 3.8 mL / min, and after extraction, the concentration of the upper H2O2 aqueous solution is 100 mM. (2) In the acidification unit, an 8.7 M acetic acid aqueous solution is continuously introduced at a rate of 0.1 mL / min to obtain an H2O2 aqueous solution containing 0.2 M acetic acid; The remaining operations are the same as in Example 1, to obtain Li-containing... +With Co 2+ The leachate.

[0068] Example 7 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: (1) In the extraction unit, the flow rate of pure water is 1.9 mL / min, and after extraction, the concentration of the upper H2O2 aqueous solution is 200 mM. (2) In the acidification unit, a 4.4 M acetic acid aqueous solution is continuously introduced at a rate of 0.1 mL / min to obtain an H2O2 aqueous solution containing 0.2 M acetic acid; The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0069] The recovery efficiency of LiCoO2 in Examples 3-7 is as follows: Figure 6 As shown, under constant acetic acid concentration, the recovery efficiency of LiCoO2 gradually increases with increasing H2O2 concentration and then stabilizes. After one hour of operation, when the H2O2 concentration is 10 mM, the LiCoO2 recovery efficiency... + and Co 2+ The leaching concentrations were 0.9 mM and 0.1 mM, respectively, and the dissolution amounts were 0.07 mmol / h, respectively. -1 and 0.03 mmol h -1 As the H2O2 concentration increases, the LiCoO2 degradation efficiency gradually increases, reaching a peak at 50 mM. + and Co 2+ The concentrations reached 34.4 mM and 33.3 mM, respectively, with dissolution amounts of 2.65 mmol / h. -1 and 2.57 mmol h -1 Increasing the H2O2 concentration did not significantly improve the degradation efficiency.

[0070] Example 8 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: In the acidification unit, an 8.7 M acetic acid aqueous solution is continuously introduced at a rate of 0.1 mL / min to obtain an H2O2 aqueous solution containing 0.1 M acetic acid.

[0071] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0072] Example 9 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: In the acidification unit, an 8.7 M acetic acid aqueous solution is continuously passed through at a rate of 0.2 mL / min to obtain an H2O2 aqueous solution containing 0.2 M acetic acid.

[0073] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0074] Example 10 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is continuously introduced at a rate of 0.3 mL / min to obtain an aqueous solution of H2O2 containing 0.5 M acetic acid.

[0075] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0076] Example 11 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is continuously introduced at a rate of 1 mL / min to obtain an aqueous solution of H2O2 containing 2 M acetic acid.

[0077] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0078] Example 12 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is passed into an aqueous H2O2 solution at a rate of 1.5 mL / min to obtain an aqueous H2O2 solution containing 3 M acetic acid.

[0079] The recovery efficiency of LiCoO2 in Examples 8-12 is as follows: Figure 7As shown, under constant H₂O₂ concentration, the degradation efficiency of LiCoO₂ first increases and then decreases with increasing acetic acid concentration. Specifically, after one hour of device operation, under 0.1 M acetic acid, the Li in LiCoO₂... + and Co 2+ The leaching concentrations were 19.6 mM and 17.8 mM, respectively, and the dissolution amounts were 1.55 mmol / h, respectively. -1 and 1.41 mmol h -1 As the acid concentration is gradually increased, the degradation efficiency gradually increases until it reaches a concentration of 1 M, at which point the degradation efficiency approaches its peak, i.e., Li + and Co 2+ The concentrations reached 52.8 mM and 49.5 mM, respectively, with dissolution amounts of 4.14 mmol / h. -1 and 3.88 mmol h -1 When the acid concentration was further increased to 2 M, the ion concentration did not increase significantly; however, when the acid concentration was 3 M, the concentration of leached metal ions decreased, i.e., Li... + and Co 2+ The concentrations reached 34.9 mM and 34.1 mM, respectively, corresponding to dissolution amounts of 2.68 mmol / h. -1 and 2.62 mmol h -1 .

[0080] Example 13 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: The acidified H2O2 aqueous solution was fed into the solid bed recovery unit filled with waste electrode material at a flow rate of 1.6 mL / min.

[0081] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0082] Example 14 A method for recycling lithium-ion battery cathode materials using a solar-powered series recycling system differs from Example 1 only in that: The acidified H2O2 aqueous solution was fed into the solid bed recovery unit filled with waste electrode material at a flow rate of 2.0 mL / min.

[0083] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0084] The recovery efficiency of LiCoO2 in Examples 1, 13, and 14 is as follows: Figure 8 As shown, under constant H2O2 and acetic acid concentrations, as the flow rate of the acidified H2O2 aqueous solution entering the solid-bed recovery unit gradually increases, the Li in the LiCoO2 leachate decreases. + and Co 2+ The concentration and total amount gradually decreased. After 1 hour of operation, the optimal degradation efficiency was reached at 1.3 mL / min, with Li... + and Co 2 + The leaching concentrations were 52.8 mM and 49.5 mM, respectively, and the dissolution amounts were 4.14 mmol / h, respectively. -1 and 3.88 mmol h -1 At 1.6 mL / min, Li + and Co 2+ The leaching concentrations were 32.4 mM and 31.7 mM, respectively, and the dissolution amounts were 3.20 mmol / h, respectively. -1 and 3.14 mmol h -1 At 2.0 mL / min, Li + and Co 2+ The leaching concentrations were 23.9 mM and 23.7 mM, respectively, and the dissolution amounts were 2.88 mmol / h, respectively. -1 and 2.88 mmol h -1 .

[0085] Comparative Example 1 A method for recycling lithium-ion battery cathode materials using a series recycling system differs from Example 1 only in that: The photocatalytic device was not exposed to light to verify the role of H2O2 in the recovery of electrode materials.

[0086] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0087] Comparative Example 2 A method for recycling lithium-ion battery cathode materials using a series recycling system differs from Example 1 only in that: In the acidification unit, an 8.7 M acetic acid aqueous solution is continuously introduced at a rate of 0.1 mL / min to obtain an H2O2 aqueous solution containing 0.1 M acetic acid.

[0088] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0089] Comparative Example 3 A method for recycling lithium-ion battery cathode materials using a series recycling system differs from Example 1 only in that: In the acidification unit, an 8.7 M acetic acid aqueous solution is continuously passed through at a rate of 0.2 mL / min to obtain an H2O2 aqueous solution containing 0.2 M acetic acid.

[0090] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0091] Comparative Example 4 A method for recycling lithium-ion battery cathode materials using a series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is continuously introduced at a rate of 0.3 mL / min to obtain an aqueous solution of H2O2 containing 0.5 M acetic acid.

[0092] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0093] Comparative Example 5 A method for recycling lithium-ion battery cathode materials using a series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is continuously introduced at a rate of 1 mL / min to obtain an aqueous solution of H2O2 containing 2 M acetic acid.

[0094] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0095] Comparative Example 6 A method for recycling lithium-ion battery cathode materials using a series recycling system differs from Example 1 only in that: In the acidification unit, glacial acetic acid is continuously introduced at a rate of 1.5 mL / min to obtain an aqueous solution of H2O2 containing 3 M acetic acid.

[0096] The remaining operations are the same as in Example 1, to obtain Li-containing... + With Co 2+ The leachate.

[0097] The recovery efficiency of LiCoO2 in Comparative Examples 1-6 is as follows: Figure 9As shown, in the absence of H2O2, acetic acid alone has a limited effect on the degradation of LiCoO2. Although the degradation efficiency of LiCoO2 increases to some extent with increasing acid concentration, reaching a peak at 3 M acetic acid, i.e., Li... + and Co 2+ The dissolution concentrations reached 8.5 mM and 4.1 mM, respectively, and the dissolution amounts were 0.64 mmol / h. -1 and 0.31 mmol h -1 However, the degradation performance was far lower than that of acid solutions containing H2O2, indicating that the acetic acid concentration itself has a limited contribution to the degradation efficiency of LiCoO2, proving the essential role of H2O2 in the electrode recovery process.

[0098] Comparative Example 7 A method for recovering lithium-ion battery cathode materials using a batch reactor differs from Example 1 only in that: An aqueous solution of H2O2 containing 1 M acetic acid was prepared using the same apparatus and method as in Example 1. After one hour of apparatus operation, 80 mL of the above aqueous solution containing 1 M acetic acid was collected and added to a batch reactor. The reactor was heated to 80 °C, and 800 mg of LiCoO2 was added while stirring. The stirring was continued for 1 hour. Unreacted electrode material was filtered off to obtain a Li-containing solution. + With Co 2+ The leachate.

[0099] The recovery efficiency of LiCoO2 in Example 1 and Comparative Example 7 is as follows: Figure 10 As shown, during the 1-hour reaction, although the reaction in the batch reactor was rapid, the metal ion concentration remained constant after 10 minutes. This is due to the rapid decomposition of H₂O₂ by transition metal cations. Ultimately, after 1 hour of reaction, Li + and Co 2+ The dissolution concentrations reached 36.2 mM and 38.2 mM, respectively, and the dissolution amounts were 3.05 mmol / h, respectively. -1 and 2.90 mmol h -1 In contrast, after one hour of operation, the continuous flow series recovery device of the present invention showed a significantly higher concentration of metal ions in the leachate than the batch reactor, and the degradation of LiCoO2 exhibited a linear increasing trend with operating time, yielding Li... + and Co 2+ The dissolution concentrations reached 53 mM and 50 mM, respectively, and the dissolution amounts were 4.14 mmol / h. -1 and 3.88 mmol h -1 This further demonstrates the advantages of the device and method provided by the present invention in terms of recycling efficiency.

[0100] Application examples use Figure 1 The solar-powered lithium-ion battery cathode material series recovery device shown is used to recover lithium-ion battery cathode materials, and the recovered metal ions are further processed by chemical precipitation to obtain lithium carbonate, as detailed below: Oil phase preparation: Dissolve DTAQ (620 mg) in benzyl alcohol (200 mL) and sonicate for 10 minutes to form a uniformly dispersed solution.

[0101] At the photocatalytic unit, the oil phase and oxygen are mixed and introduced into the flat-plate photocatalytic device through a T-valve at flow rates of 8 mL / min and 16 mL / min, respectively, using outdoor natural light for illumination. Next, the reacted oil phase and external pure water (5.5 mL / min) are simultaneously introduced into the extraction unit to fully extract H2O2 from the oil phase into the aqueous phase. The resulting upper H2O2 aqueous solution (concentration approximately 55 mM) enters the acidification unit, while the lower oil phase is recovered and enters the next reaction cycle. At the acidification unit, glacial acetic acid is introduced into the H2O2 aqueous solution at a certain flow rate (0.4 mL / min) to obtain an H2O2 aqueous solution containing 1 M acetic acid. Finally, the acidified H2O2 aqueous solution is introduced into a solid-bed recovery unit filled with waste electrode material at a flow rate of 1.3 mL / min. The recovery device is tilted at 12°, and LiCoO2 is used as the electrode material. The initial feed is 800 mg, followed by an hourly replenishment of 400 mg. The heating medium temperature is maintained at approximately 80 °C through concave mirror focusing or the photothermal effect of light-absorbing tape. Metal ions gradually leach from the positive electrode material and continuously flow out from the outlet, yielding Li-containing... + With Co 2+ The leachate.

[0102] For the collected leachate, a stepwise precipitation method was used to selectively recover the metal: 270 mg of oxalic acid was added to every 50 mL of leachate, stirred for 30 min, filtered and washed with water to obtain a pink precipitate, and cobalt oxalate solid and lithium-rich solution were obtained; 60 mL of saturated sodium carbonate aqueous solution was added to the lithium-rich solution, heated at 95°C for 2 h, filtered and washed with water multiple times to obtain a white precipitate, and finally lithium carbonate solid was obtained.

[0103] like Figure 12 , 13 As shown, on July 21, 2026, from 11:00 to 17:00, the concentration of H2O2 produced by the photocatalytic unit remained between 55.4 and 63.7 mM, with an average production rate of 18.3 mmol / h. -1 The H2O2 produced in one day was used entirely for electrode material recovery, achieving the recovery of 21.8 g of LiCoO2 in one day, yielding 3.67 g of Li2CO3 and 13.7 g of CoC2O4.

[0104] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A solar-driven series recycling system for lithium-ion battery cathode materials, characterized in that, It includes a planar photocatalytic unit, an extraction unit, an acidification unit, and a solid-bed electrode recovery unit connected in series, wherein, The flat-plate photocatalytic unit is provided with an oil phase inlet, a gas phase inlet, and a reaction liquid outlet. It is used to allow the oil phase containing the photocatalyst to form a continuous gas-liquid two-phase flow with the oxygen-containing gas and carry out a photocatalytic reaction to generate H2O2. After the reaction, the oil phase is sent to the extraction unit through the reaction liquid outlet. The extraction unit is equipped with a reaction liquid inlet, a pure water inlet, and an H2O2 aqueous solution outlet connected to the reaction liquid outlet. It is used to introduce pure water to extract H2O2 from the oil phase after the reaction into the aqueous phase, and to control the concentration of the obtained H2O2 aqueous solution by adjusting the pure water flow rate. The resulting H2O2 aqueous solution with the target concentration is sent to the acidification unit through the H2O2 aqueous solution outlet. The acidification unit is equipped with an H2O2 aqueous solution inlet, an acid solution inlet, and an acidic H2O2 aqueous solution outlet connected to the H2O2 aqueous solution outlet. It is used to introduce an acid solution to mix with the H2O2 aqueous solution, and to control the acid concentration of the resulting acidic H2O2 aqueous solution by adjusting the concentration or flow rate of the acid solution. The resulting acidic H2O2 aqueous solution with the target acid concentration is sent to the solid bed electrode recovery unit through the acidic H2O2 aqueous solution outlet. The solid-bed electrode recovery unit is equipped with an acidic H2O2 aqueous solution inlet, a feeding port, and a leachate outlet connected to the acidic H2O2 aqueous solution outlet. It is used to flush the cathode material to be recovered with a continuously flowing acidic H2O2 aqueous solution to leach out metal ions. The resulting leachate containing metal ions flows out through the leachate outlet and is collected.

2. The solar-driven lithium-ion battery cathode material series recycling system according to claim 1, characterized in that, The planar photocatalytic unit includes a planar photocatalytic device, which is assembled by a tube passing through a pre-drilled hole on a support plate. The gas-liquid two-phase continuous flow enters the planar photocatalytic device through the tube to carry out the photocatalytic reaction. The diameter of the duct is 1-2 mm larger than the outer diameter of the pipe.

3. The solar-driven lithium-ion battery cathode material series recycling system according to claim 2, characterized in that, The pipe is made of polytetrafluoroethylene; And / or, the material of the support plate is selected from one or more of polyethylene, polyvinyl chloride, polypropylene, and polymethyl methacrylate; And / or, the support plate has a first side and a second side, on which multiple layers of staggered channels are respectively opened, and the left-right spacing L of adjacent channels in the same layer is 20-30 mm, and the spacing H between two adjacent layers of channels is 10-20 mm; the pipes are inserted into the channels and arranged closely through the holes of the channels to form a multi-layer pipe arrangement structure.

4. The solar-driven lithium-ion battery cathode material series recycling system according to claim 1, characterized in that, The solid-bed electrode recovery unit includes one or more tubular reaction devices arranged in parallel. Each tubular reaction device is provided with a feed port, an acidic H2O2 aqueous solution inlet, and a leachate outlet. The feed port is used to feed the cathode material to be recovered into the tubular reaction device.

5. The solar-driven lithium-ion battery cathode material series recycling system according to claim 4, characterized in that, A heating device is provided around the tubular reaction device to regulate the temperature of the tubular reaction device; And / or, a porous plate is provided at the leachate outlet of the tubular reaction device, and at least one porous filter membrane is laid on the surface of the porous plate away from the leachate outlet, the porous filter membrane being used to prevent the positive electrode material in the tubular reaction device from being lost with the leachate; And / or, the tubular reaction device is inclined as a whole, and the inlet end of the acidic H2O2 aqueous solution of the tubular reaction device is higher than the outlet end of the leachate, with an inclination angle of 0-90°.

6. The solar-driven lithium-ion battery cathode material series recycling system according to claim 5, characterized in that, The tubular reaction device is fitted with an outer glass tube, and the annular gap between the outer glass tube and the tubular reaction device forms a heating medium circulation jacket. The outer glass tube is provided with a heating medium inlet and a heating medium outlet. The porous filter membrane is made of one or more of glass fiber, cellulose and non-woven fabric. The porous filter membrane has a pore size of 1-2 μm and a thickness of 1-3 mm; The tilt angle is 10-30°.

7. A method for recycling lithium-ion battery cathode materials using the system described in any one of claims 1-6, characterized in that, Includes the following steps: S1. The oil phase containing the photocatalyst is mixed with oxygen-containing gas to form a continuous gas-liquid two-phase flow, which is then introduced into a flat-plate photocatalytic unit to carry out a photocatalytic reaction and generate an oil phase containing H2O2. S2. The oil phase containing H2O2 and pure water are continuously passed into the extraction unit to extract H2O2 from the oil phase into the aqueous phase, and an aqueous solution with the target concentration of H2O2 is obtained by adjusting the rate of pure water flow. S3. The H2O2 aqueous solution and the acid solution are simultaneously introduced into the acidification unit for mixing, and an acidic H2O2 aqueous solution with the target acid concentration is obtained by adjusting the concentration or flow rate of the acid solution. S4. The acidic H2O2 aqueous solution is continuously passed into the solid-bed electrode recovery unit, so that it flows through the cathode material to be recovered placed in the solid-bed electrode recovery unit, continuously flushing and leaching metal ions from the cathode material, and collecting the leachate containing metal ions.

8. The method according to claim 7, characterized in that, In step S1, the oil phase contains non-water-soluble alcohols and / or amine reagents. The non-water-soluble alcohols are selected from one or more of n-pentanol, isopentanol, n-hexanol, isohexanol, 2-ethylhexanol, n-octanol, isooctanol, n-decanol, isodecanol, and benzyl alcohol. The amine reagents are selected from one or more of aromatic benzylamine derivatives and tetrahydroisoquinoline derivatives. And / or, in step S1, the concentration of the photocatalyst in the oil phase is 0.1-3 g / L; the photocatalyst is selected from one or more of perylene imide derivatives, anthraquinone and its derivatives, fluorenone and its derivatives, and polymer photocatalysts; And / or, in step S1, the flow rate ratio of the oil phase to the oxygen-containing gas is (0.3-1.2):1; And / or, in step S1, the photocatalytic reaction is carried out under light intensity of 50-500 mW. cm -2 Under the conditions; And / or, in step S2, the concentration of the H2O2 aqueous solution is 10-300 mM; And / or, in step S3, the acid concentration in the acidic H2O2 aqueous solution is 0.1-4 M; the acid in the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, ascorbic acid, formic acid, acetic acid, propionic acid, and oxalic acid; And / or, in step S4, the cathode material to be recycled is selected from LiCoO2, LiFePO4, LiCo x Ni y Mn 1-x-y One or more of O2, LiMn2O4, and black powder obtained from dismantling lithium-ion battery positive electrode sheets, wherein O <x,0<y,x+y<1。 9. The method according to claim 8, characterized in that, The photocatalyst is a compound with the following structure: 。 10. The method according to claim 7, characterized in that, In step S4, the flow rate of the acidic H2O2 aqueous solution into the solid-state electrode recovery unit is 1-3 mL / min; And / or, the temperature of the solid-state bed electrode recovery unit is 50-90 ℃.

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