A method for recycling positive electrode materials of light-driven lithium-ion batteries

Abstract

The present invention discloses a method for recycling positive electrode materials of lithium-ion batteries driven by light, comprising the following steps: constructing a water / oil two-phase light-driven recycling system, wherein a photocatalyst is dispersed in an upper oil phase, and a lithium-ion battery positive electrode material and an acid are dispersed in a lower water phase; applying light to the water / oil two-phase light-driven recycling system under an oxygen or air atmosphere to drive a catalytic reaction, causing metal ions to leach from the positive electrode material of the lithium-ion battery, and then using a chemical precipitation method to achieve metal ion recovery. The present invention proposes a green method for recycling positive electrode materials of lithium-ion batteries driven by photocatalysis, which achieves efficient recovery of high-value metals such as lithium and cobalt by coupling the photocatalytic-photothermal synergistic effect and oil-water interface regulation. Compared with existing recycling processes, the present invention abandons the external heating device and the addition of chemical reducing agents, providing a green, low-energy and low-cost strategy for the recycling of lithium-ion batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion battery recycling, and in particular to a method for recycling positive electrode materials of light-driven lithium ion batteries. Background Art

[0002] Lithium-ion batteries, with their excellent energy storage performance, are widely used in many fields, including new energy vehicles, smart grids, and portable electronic devices. However, the large amount of toxic electrolytes, heavy metals, and other pollutants generated during the large-scale production and disposal of lithium-ion batteries pose a major threat to the stability of ecosystems and human health and safety. At the same time, the unsustainable mining and disposal of high-value metals such as lithium, cobalt, and nickel not only causes serious environmental degradation but also leads to a huge waste of resources. Therefore, the recycling and reuse of key metals in lithium-ion batteries is of great significance both in terms of environmental protection and economic development.

[0003] At present, in the field of lithium-ion battery cathode material recycling, the main process is hydrometallurgical process. This process uses acid to provide protons and anions to achieve metal leaching, which has the advantages of mild reaction conditions and high metal recovery rate. Its reaction kinetics is similar to that of high-valent metals (such as Co 3+ ) is closely related to the reduction process of H2O2. In actual operation, it is usually necessary to strategically introduce H2O2 as a reducing agent to effectively accelerate the reaction process. However, this technical system still faces many severe challenges in practical application: First, H2O2 is mainly prepared by the anthraquinone method in industry. This method has the disadvantages of high energy consumption and high pollution, resulting in a significant increase in carbon emissions from the entire battery recycling industry chain; second, high-concentration H2O2 has the risk of combustion and explosion during storage and use, which greatly increases the difficulty of production safety management; third, H2O2 will decompose rapidly in a heated environment and the presence of transition metal ions, causing its effective concentration to decay rapidly. In order to maintain the reaction efficiency, it needs to be continuously replenished, which not only significantly increases the reagent cost, but also makes the process flow control extremely complicated due to frequent operations. In addition, the existing technology also requires continuous heating to improve the reaction kinetics, which further aggravates energy loss and increases production costs.

[0004] In summary, developing a sustainable lithium-ion battery cathode material recycling strategy that combines high efficiency and energy-saving characteristics with industrial application potential has become a key technical issue that needs to be urgently addressed in this field. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a light-driven lithium-ion battery cathode material recycling method, which has the advantages of being green and low in energy consumption, and can achieve efficient extraction and recovery of high-value metal elements in the cathode material.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for recovering positive electrode materials of lithium-ion batteries driven by light comprises the following steps: constructing a water / oil two-phase light-driven recovery system, wherein a photocatalyst is dispersed in an upper oil phase, and a positive electrode material of the lithium-ion battery and an acid are dispersed in a lower water phase; applying light to the water / oil two-phase light-driven recovery system in an oxygen or air atmosphere to drive a catalytic reaction, thereby leaching metal ions from the positive electrode material of the lithium-ion battery, and then recovering the metal ions by a chemical precipitation method.

[0008] In the light-driven lithium-ion battery cathode material recovery method provided by the present invention, the photocatalyst dispersed in the oil phase generates hydrogen peroxide (H2O2) under light and diffuses into the water phase. With the assistance of the light-induced thermal effect, the high-valent metal in the lithium-ion battery cathode material is promoted to be reduced, such as the high-valent Co in LiCoO2. 3+ ions are reduced to Co 2+ ions, and then destroy and dissolve the electrode material lattice in an acidic environment to achieve Li + and Co 2+ Leaching.

[0009] The present invention proposes a green method for recycling positive electrode materials of lithium-ion batteries driven by photocatalysis, which realizes the efficient recovery of high-value metals such as lithium and cobalt by coupling the photocatalytic-photothermal synergistic effect and oil-water interface regulation. This method uses light energy as the only energy input source, and utilizes a photocatalyst to convert oxygen into hydrogen peroxide in situ under light, and simultaneously realizes the self-supply of reducing agents and the self-heating of the reaction system, thereby achieving efficient leaching of metal ions. Compared with the existing recycling process, the present invention abandons the external heating device and the addition of chemical reducing agents, providing a green, low-energy and low-cost strategy for the recycling of lithium-ion batteries, maximizing the photocatalytic efficiency, and meeting the needs of continuous production.

[0010] Furthermore, to ensure the overall reaction efficiency and stability of the system, the photocatalyst should be an organic semiconductor material with hydrophobicity and thermal / acid stability. Considering that the rigid conjugated skeleton can enhance the light absorption capacity, the photocatalyst is selected from one or more of the following T1-T3 structures:

[0011] 、 、 .

[0012] Furthermore, the photocatalyst is obtained by reacting an aldehyde monomer and an amino monomer in an organic solvent at 80-150°C;

[0013] The aldehyde monomer is 2,3,6,7,10,11-hexa(4-formylphenyl)triphenylene, and the amine monomer is 2,5-diamino-1,4-benzodithiophene dihydrochloride, 2,5-diamino-1,4-dihydroxybenzene dihydrochloride or 1,2,4,5-benzenetetramine tetrahydrochloride.

[0014] Furthermore, the structural formula of the 2,3,6,7,10,11-hexa(4-formylphenyl)triphenylene is The structural formula of the 2,5-diamino-1,4-benzodithiophene dihydrochloride is The structural formula of the 2,5-diamino-1,4-dihydroxybenzene dihydrochloride is The structural formula of the 1,2,4,5-benzenetetramine tetrahydrochloride is .

[0015] Specifically, under oxygen (or air) conditions, the aldehyde group and the amine group first produce an imine bond through a Schiff base condensation reaction, and then under the oxidative action of molecular oxygen, a dehydrogenation cyclization reaction occurs between the imine and the thiol group (synthesis T1) or hydroxyl group (synthesis T2) or amino group (synthesis T3), finally forming a stable benzobisazole linking unit. The prepared photocatalyst has a fully conjugated skeleton structure and excellent chemical stability.

[0016] Furthermore, the organic solvent is N,N-dimethylformamide (DMF).

[0017] Furthermore, the concentration of the aldehyde monomer in the organic solvent is 1.5-2 mM, preferably 1.8 M.

[0018] Furthermore, the concentration of the amino monomer in the organic solvent is 5-6 mM, preferably 5.6 M.

[0019] Preferably, the photocatalyst is a compound containing a thiazole ring and a triphenylene unit, and the structural formula is:

[0020] .

[0021] Furthermore, the concentration of the photocatalyst in the oil phase is 0.1-100 g / L, preferably 0.5-30 g / L, and more preferably 1-3 g / L.

[0022] Furthermore, the oil phase is a water-insoluble alcohol solvent with a density lower than that of water and a boiling point greater than 100°C.

[0023] Furthermore, the oil phase is selected from one or more of n-pentanol, isopentanol, n-hexanol, isohexanol, 2-ethylhexanol, n-octanol, isooctyl alcohol, n-decanol and isodecanol.

[0024] Preferably, n-octanol is selected as the oil phase from the perspectives of low viscosity, high hole consumption rate and procurement cost.

[0025] Furthermore, the lithium-ion battery positive electrode material is selected from LiCoO2, LiFePO4, LiCo x Ni y Mn 1-x-y One or more of O2, LiMn2O4, LiNiCoAlO2, LiV2O4, Li2FeTiO4; wherein, 0 <x,0<y,x+y<1。

[0026] Furthermore, the concentration of the lithium-ion battery positive electrode material in the aqueous phase is 0.1-100 g / L, preferably 0.5-30 g / L, and more preferably 1-10 g / L.

[0027] Furthermore, the acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, formic acid, acetic acid, citric acid, maleic acid, malic acid and ascorbic acid.

[0028] Preferably, considering factors such as cost and efficiency, the acid is acetic acid.

[0029] Furthermore, the concentration of the acid in the aqueous phase is 0.05-5 M, preferably 0.05-2 M, and more preferably 0.2-1.0 M.

[0030] Furthermore, the volume ratio of the oil phase to the water phase is (0.1-10):1, preferably 1:3-3:1.

[0031] Furthermore, sunlight or artificial light sources may be used to apply illumination, and Fresnel lenses may be used to increase light intensity and thermal effects.

[0032] Furthermore, the artificial light source is a xenon lamp or an LED.

[0033] Furthermore, the intensity of the illumination is 50-600 mW·cm -2 , preferably 200-600 mW·cm -2 .

[0034] Furthermore, the temperature of the water / oil two-phase light-driven recovery system is 60-90°C, preferably 80°C.

[0035] The beneficial effects of the present invention are:

[0036] 1. The light-driven lithium-ion battery positive electrode material recovery method provided by the present invention does not require external addition of H2O2. H2O2 is continuously supplied in situ at room temperature and pressure through photochemistry to accelerate the reduction of metal ions, avoiding the defect of the existing method that requires continuous replenishment of reducing agents. There is no need for manual monitoring and replenishment of reducing agents, saving the cost of purchasing, transporting and storing reducing agents, and reducing the frequency of manual intervention; the dynamic mass transfer process effectively alleviates the problem of catalyst degradation caused by the accumulation of H2O2 concentration, maintains the stability of the photocatalyst and the continuous operation of the system; in the water / oil two-phase light-driven recovery system, H2O2 generation and metal ion leaching are carried out continuously in the same reactor, reducing the number of equipment used; the energy input of the water / oil two-phase light-driven recovery system is completely dependent on light energy, and only the photothermal effect needs to be used to provide heat to achieve heating, without the need for the heating device in the traditional system, further reducing energy consumption and cost.

[0037] 2. The physical phase separation strategy in the method for recycling positive electrode materials of light-driven lithium-ion batteries provided by the present invention successfully blocks the competitive absorption of incident light by dark positive electrode materials, thereby ensuring the light energy capture efficiency of the photocatalyst; the photocatalytic and chemical acid etching processes are carried out independently in the two-phase systems that are immiscible with each other, thereby realizing the continuous collection of the lower layer of metal ion solution and facilitating the dynamic replenishment of the acid solution; the mass transfer barrier formed at the interface of the two phases can effectively prevent the contamination of the photocatalyst by the dissolved metal ions, thereby ensuring the stability of the photocatalytic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the reaction system for recycling positive electrode materials of light-driven lithium-ion batteries provided by the present invention.

[0039] Figure 2 The infrared structural characterization spectrum of the photocatalyst shown is T1-T3 structure.

[0040] Figure 3 Solid photocatalyst represented by T1-T3 structure 13 C NMR spectrum.

[0041] Figure 4 These are morphological characterization diagrams of the photocatalysts represented by the T1-T3 structures; among them, a is a scanning electron microscope (SEM) image of the photocatalyst represented by the T1 structure, b is the SEM image of the photocatalyst represented by the T2 structure, c is the SEM image of the photocatalyst represented by the T3 structure, d is a transmission electron microscope (TEM) image of the photocatalyst represented by the T1 structure, e is the TEM image of the photocatalyst represented by the T2 structure, and f is the TEM image of the photocatalyst represented by the T3 structure.

[0042] Figure 5 Recovering Li from the positive electrode material of the light-driven lithium-ion battery of Example 1 + and Co2+ The left picture shows the Li dissolved from LiCoO2 per unit mass of photocatalyst. + and Co 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + and Co 2+ Dissolution efficiency data graph.

[0043] Figure 6 Recovering Li from the positive electrode material of the light-driven lithium-ion battery of Example 1-3 + and Co 2+ Li dissolved from LiCoO2 per unit mass of photocatalyst after 4 hours of illumination + and Co 2+ Comparison chart of the amount of substance.

[0044] Figure 7 Recovering Li from the positive electrode material of the light-driven lithium-ion battery of Example 4 + and Co 2+ The left picture shows the Li dissolved from LiCoO2 per unit mass of photocatalyst. + and Co 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + and Co 2+ Dissolution efficiency data graph.

[0045] Figure 8 Recovering Li from the positive electrode material of light-driven lithium-ion batteries of Examples 1 and 5-8 + and Co 2+ Li dissolved from LiCoO2 per unit mass of photocatalyst after 4 hours of illumination + and Co 2+ Comparison chart of the amount of substance.

[0046] Figure 9 Recovering Li from the positive electrode material of light-driven lithium-ion batteries of Examples 1 and 9-13 + and Co 2+ Li dissolved from LiCoO2 per unit mass of photocatalyst after 4 hours of illumination + and Co 2+ Comparison chart of the amount of substance.

[0047] Figure 10 Recovering Li from the positive electrode material of the light-driven lithium-ion battery of Example 14 + Li dissolved from LiFePO4 per unit mass of photocatalyst + The amount of substance changes over time and the corresponding Li + Dissolution efficiency data graph.

[0048] Figure 11 Recovering Li from the positive electrode material of the light-driven lithium-ion battery of Example 15 + 、Co 2+ 、Ni 2+ and Mn 2+ The test results are shown in the figure below; the left figure shows the unit mass of photocatalyst from LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 Li dissolved in O2 + 、Co 2+ 、Ni 2+ and Mn 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + 、Co 2+ 、Ni 2+ and Mn 2+ Dissolution efficiency data graph.

[0049] Figure 12 Recovering Li from the positive electrode material of the light-driven lithium-ion battery of Example 16 + and Co 2+ The left picture shows the Li dissolved from LiCoO2 per unit mass of photocatalyst. + and Co 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + and Co 2+ Dissolution efficiency data graph.

[0050] Figure 13 Recovering Li from the positive electrode material of light-driven lithium-ion batteries of Examples 1 and 17-18 + and Co 2+ Li dissolved from LiCoO2 per unit mass of photocatalyst after 4 hours of illumination + and Co 2+ Comparison chart of the amount of substance.

[0051] Figure 14 Comparative Example 1: Recycling of Li from the positive electrode material of a light-driven lithium-ion battery + and Co 2+ The left picture shows the Li dissolved from LiCoO2 per unit mass of photocatalyst. + and Co 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + and Co 2+ Dissolution efficiency data graph.

[0052] Figure 15 Comparative Example 2: Recycling of Li from the positive electrode material of a light-driven lithium-ion battery + and Co2+ The left picture shows the Li dissolved from LiCoO2 per unit mass of photocatalyst. + and Co 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + and Co 2+ Dissolution efficiency data graph.

[0053] Figure 16 Comparative Example 3: Recycling of Li from the positive electrode material of a light-driven lithium-ion battery + and Co 2+ The left picture shows the Li dissolved from LiCoO2 per unit mass of photocatalyst. + and Co 2+ The trend of the amount of substance changing with time; the right picture shows Li after 4 hours of light exposure + and Co 2+ Dissolution efficiency data graph.

[0054] Figure 17 This is the experimental result diagram of the cyclic stability test of Test Example 1.

[0055] Figure 18 Schematic diagram of an outdoor experimental device based on natural sunlight; wherein, a is a schematic diagram of the outdoor experimental device, and b is an enlarged view.

[0056] Figure 19 Recovering Li from cathode materials of light-driven lithium-ion batteries under sunlight irradiation + and Co 2+ The trend of metal ion dissolution and sunlight intensity over time.

[0057] Figure 20 This is a graph showing the daily metal ion dissolution and weather trends during a 30-day outdoor empirical study for Test Example 2. DETAILED DESCRIPTION

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] The present invention provides a method for recycling positive electrode materials of lithium-ion batteries driven by light, comprising the following steps: constructing a water / oil two-phase light-driven recycling system, wherein a photocatalyst is dispersed in an upper oil phase, and a lithium-ion battery positive electrode material and an acid are dispersed in a lower water phase; applying light to the water / oil two-phase light-driven recycling system in an oxygen or air atmosphere to drive a catalytic reaction, thereby leaching metal ions from the lithium-ion battery positive electrode material, and then using a chemical precipitation method to realize the recovery of the metal ions.

[0060] In a specific embodiment, the schematic diagram of the reaction system for light-driven lithium-ion battery cathode material recovery is as follows: Figure 1 As shown, the reaction in the water / oil two-phase light-driven recovery system is carried out in a double-layered glass two-phase reactor (with an inner quartz layer for light transmission and an outer jacket for temperature control). The top is open to a gas inlet, and a magnetic stirrer is installed at the bottom for stirring. An aqueous phase containing lithium-ion battery cathode materials and acid is injected into the bottom of the reactor, followed by an oil phase containing a photocatalyst. The density difference and interfacial properties of the two phases achieve spatial separation, forming a clear interface. Light is illuminated through the transparent reactor top, acting on the oil phase to drive the reaction, stimulating the photocatalyst to produce H2O2. This photothermal effect heats the reaction solution, accelerating the reaction. The generated H2O2 diffuses in situ into the aqueous phase, promoting the reduction of high-valent metal ions in the cathode material, thereby accelerating the dissolution and leaching of metal ions from the lithium-ion battery cathode material. During the reaction, the aqueous phase can be sampled and analyzed for metal ion concentration, and then chemical precipitation is used to recover the metal ions. In addition, a leachate collector is used to collect the metal ion solution and replace the aqueous phase.

[0061] In one embodiment of the present invention, the photocatalyst is selected from one or more of the following T1-T3 structures:

[0062] 、 、 .

[0063] Figure 2 The infrared structural characterization spectrum of the photocatalyst shown is T1-T3 structure. Figure 3 Solid photocatalyst represented by T1-T3 structure 13 C NMR spectrum. Figure 4 These are morphological characterization diagrams of the photocatalysts represented by the T1-T3 structures; wherein, a is the SEM image of the photocatalyst represented by the T1 structure, b is the SEM image of the photocatalyst represented by the T2 structure, c is the SEM image of the photocatalyst represented by the T3 structure, d is the TEM image of the photocatalyst represented by the T1 structure, e is the TEM image of the photocatalyst represented by the T2 structure, and f is the TEM image of the photocatalyst represented by the T3 structure.

[0064] 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 the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0065] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are all commercially available unless otherwise specified.

[0066] Example 1

[0067] A method for recycling positive electrode materials of light-driven lithium-ion batteries, using Figure 1 The reaction system for recycling positive electrode materials of light-driven lithium-ion batteries shown in FIG. 1 specifically includes the following steps:

[0068] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0069] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio (volume ratio of oil phase to aqueous phase) of 1:1.

[0070] A water / oil two-phase light-driven recycling system was constructed. The oil phase was slowly added to the water phase to spontaneously form a stable oil-water interface. Oxygen was introduced into the water / oil two-phase light-driven recycling system. The reactor was then sealed and irradiated with a 300 W xenon lamp light source. A Fresnel lens was used to adjust the light intensity to 500 mW·cm -2 The range is to maintain the water phase temperature at about 80 ℃, and the metal ions are gradually leached from the positive electrode material of the lithium ion battery. After the leaching process is completed, the Li + and Co 2+ The leachate is then selectively recovered by a step-by-step precipitation method. 65 mg of oxalic acid is added to every 50 mL of leachate and stirred for 30 minutes. The resulting pink precipitate is filtered and washed with water to yield cobalt oxalate solid and a lithium-rich solution. Subsequently, 10 mL of saturated sodium carbonate aqueous solution is added to the lithium-rich solution, heated at 95°C for 2 hours, and the resulting white precipitate is filtered and washed with water multiple times to yield lithium carbonate solid.

[0071] Example 2

[0072] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0073] Oil phase preparation: The photocatalyst (30 mg) shown in structure T2 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0074] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0075] Example 3

[0076] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0077] Oil phase preparation: The photocatalyst (30 mg) shown in the structure T3 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0078] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1. During the reaction process of Examples 1-3, aqueous phase samples (0.15 mL) were taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After the filtrate was diluted to a certain ratio, the LiCoO2 was analyzed by inductively coupled plasma optical emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 5 and Figure 6 As shown, Figure 5 The middle left figure shows the average amount of Li that can be leached per gram of photocatalyst within 4 hours of illumination. + and Co 2+ The change in the amount of a substance over time. + and Co 2+ The dissolution amount of α-amylase and α-amylase increased linearly with the illumination time, and the dissolution rates reached 3083 and 2555 μmol·h, respectively. -1 ·g -1 .like Figure 5 As shown in the middle right figure, after 4 hours of light exposure, Li + and Co 2+ The recovery rates (dissolution efficiencies) were 72% and 61%, respectively.

[0079] Figure 6 A comparison chart of the amount of metal ion dissolution when using photocatalysts represented by structures T1, T2, and T3, respectively, shows that the amount of metal ion dissolution is the highest when using the photocatalyst represented by structure T1, and the lowest when using the photocatalyst represented by structure T3.

[0080] Example 4

[0081] A method for recycling positive electrode materials of light-driven lithium-ion batteries comprises the following steps:

[0082] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0083] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M citric acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0084] A water / oil two-phase light-driven recycling system was constructed. The oil phase was slowly added to the water phase to spontaneously form a stable oil-water interface. Oxygen was introduced into the water / oil two-phase light-driven recycling system. The reactor was then sealed and irradiated with a 300 W xenon lamp light source. A Fresnel lens was used to adjust the light intensity to 500 mW·cm -2 The temperature of the aqueous phase is maintained at approximately 80°C, allowing metal ions to gradually leach out of the cathode material of the lithium-ion battery. The collected aqueous leachate is then precipitated and recovered using a chemical precipitation method.

[0085] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 7 As shown, Figure 7 The middle left figure shows the average amount of Li that can be leached per gram of photocatalyst within 4 hours of illumination. + and Co 2+ The change in the amount of a substance over time. + and Co 2+ The dissolution amount of α-amylase and α-amylase increased linearly with the illumination time, and the dissolution rates reached 4082 and 3805 μmol·h, respectively. -1 ·g -1 .like Figure 7 As shown in the middle right figure, after 4 hours of light exposure, Li + and Co 2+ The recoveries (dissolution efficiencies) were 96% and 89.5%, respectively.

[0086] Example 5

[0087] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0088] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (22.5 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0089] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (7.5 mL) with an oil / water volume ratio of 3:1.

[0090] Example 6

[0091] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0092] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (20 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0093] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (10 mL) with an oil / water volume ratio of 2:1.

[0094] Example 7

[0095] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0096] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (10 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0097] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (20 mL) with an oil / water volume ratio of 1:2.

[0098] Example 8

[0099] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0100] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (7.5 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0101] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (22.5 mL) with an oil / water volume ratio of 1:3.

[0102] During the reaction of Examples 5-8, water phase samples (0.15 mL) were taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 8 As shown, Figure 8 It shows that within 4 hours of illumination, the average per gram of photocatalyst in the presence of oil / water volume ratio of 1:3, Li + and Co 2+ The dissolution rates of -1 ·g -1 In addition, in Example 1 and Examples 5-8, the performance was best when the oil / water volume ratio was 1:1. When the oil / water ratio was optimized from 3:1 to 1:1, Li + and Co 2+ The dissolution amount of Li + and Co 2+ The dissolution amount decays, showing a volcanic distribution pattern.

[0103] Example 9

[0104] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0105] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.1 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0106] Example 10

[0107] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0108] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.4 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0109] Example 11

[0110] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0111] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.6 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0112] Example 12

[0113] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0114] Aqueous phase preparation: LiCoO2 (50 mg) was added to 1.0 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0115] Example 13

[0116] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0117] Aqueous phase preparation: LiCoO2 (50 mg) was added to 1.5 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0118] During the reaction of Examples 9-13, water phase samples (0.15 mL) were taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 9 As shown, Figure 9 It shows that within 4 hours of illumination, the average per gram of photocatalyst in the presence of acetic acid at a concentration of 1.5 M is Li + and Co 2+ The dissolution rates of -1 ·g -1 In addition, in Example 1 and Examples 9-13, the performance was best when the concentration of acetic acid was 0.6 M. When the concentration of acid was optimized from 0.1 M to 0.6 M, Li + and Co 2+ The dissolution amount of Li + and Co 2+ The dissolution amount decays, showing a volcanic distribution pattern.

[0119] Example 14

[0120] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0121] Aqueous phase preparation: LiFePO4 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0122] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiFePO4). After a certain proportion of dilution, the LiFePO4 was analyzed by inductively coupled plasma emission spectrometry. + Quantitative detection of content, the test results are as follows Figure 10As shown, the LiFePO4 cathode material exhibits an excellent decomposition rate in this system, achieving almost 100% complete decomposition in just 60 minutes, corresponding to Li + The dissolution rate was 15800 μmol·h -1 ·g -1 Under these experimental conditions, Li + The recovery rate reached 98.7%.

[0123] Example 15

[0124] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0125] Aqueous phase configuration: LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0126] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2). After a certain proportion of dilution, the Li + 、Co 2+ 、Ni 2+ 、Mn 2+ Quantitative detection of content, the test results are as follows Figure 11 As shown, Figure 11 The middle left figure shows the average amount of Li that can be leached per gram of photocatalyst within 4 hours of illumination. + 、Co 2+ 、Ni 2+ and Mn 2+ The change of the amount of substance over time proves that the system still maintains excellent recovery ability for complex component materials. + 、Co 2+ 、Ni 2+ and Mn 2+ The dissolution rates of the four metal ions were 4033, 845, 887.5, and 758 μmol·h, respectively. -1 ·g -1 .like Figure 11 As shown in the middle right figure, after 4 hours of light exposure, Li + 、Co 2+ 、Ni 2+ and Mn 2+The recoveries (dissolution efficiencies) were 93.6%, 82.1%, 85% and 75.9%, respectively.

[0127] Example 16

[0128] A method for recycling positive electrode materials of light-driven lithium-ion batteries comprises the following steps:

[0129] Oil phase configuration: Graphite phase carbon nitride ( g -C3N4) photocatalyst (30 mg) was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 min to form a uniformly dispersed suspension.

[0130] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0131] Oxygen was introduced into the system, and the reactor was sealed. The system was irradiated with a 300 W xenon lamp light source, and the light intensity was adjusted to 500 mW·cm using a Fresnel lens. -2 The range is to maintain the water phase temperature at around 80 °C, and metal ions are gradually leached from the positive electrode material of the lithium-ion battery.

[0132] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 12 As shown, Figure 12 The middle left figure shows the average amount of Li that can be leached per gram of photocatalyst within 4 hours of illumination. + and Co 2+ The amount of substance changes with time. 2 hours before light exposure, Li + and Co 2+ The dissolution amount of α-amylase increased with the illumination time, and the dissolution rates reached 1713 and 1258 μmol·h, respectively. -1 ·g -1 After 2 hours of light exposure, the amount of metal dissolution almost stops increasing. Figure 12 As shown in the middle right figure, after 4 hours of light exposure, Li + and Co 2+ The recoveries (dissolution efficiencies) were 43% and 29.6%, respectively.

[0133] Example 17

[0134] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0135] Oil phase preparation: The photocatalyst (15 mg) shown in structure T1 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0136] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0137] Example 18

[0138] A method for recycling positive electrode materials of light-driven lithium-ion batteries is basically the same as the method in Example 1, except that:

[0139] Oil phase preparation: The photocatalyst (45 mg) shown in structure T1 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0140] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0141] During the reaction of Examples 17-18, a water phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the Li + and Co 2+ Quantitative detection of content, the test results are as follows Figure 13 As shown, Figure 13 It shows that within 4 hours of illumination, the photocatalyst shown in the T1 structure has a concentration of 1 g / L and Li + and Co 2+ The dissolution rates of -1 ·g -1 When the catalyst concentration is 3 g / L, Li + and Co 2+ The dissolution rates of -1 ·g -1 . It was shown that the best performance was achieved when the catalyst concentration was 2 g / L.

[0142] Comparative Example 1

[0143] A method for recycling positive electrode materials of light-driven lithium-ion batteries comprises the following steps:

[0144] System solution preparation: The photocatalyst shown in the T1 structure (30 mg) was dispersed in n-octanol (15 mL), and ultrasonic dispersion was performed for 10 minutes to form a uniformly dispersed suspension. LiCoO2 (50 mg) and 0.2 mL of glacial acetic acid were directly added to the suspension.

[0145] Oxygen was introduced into the system, and the reactor was sealed. The system was irradiated with a 300 W xenon lamp light source, and the light intensity was adjusted to 500 mW·cm using a Fresnel lens. -2 The range is to maintain the water phase temperature at around 80 °C, and metal ions are gradually leached from the positive electrode material of the lithium-ion battery.

[0146] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 14 As shown, Figure 14 The middle left picture shows the Li that can be leached within 4 hours of light exposure. + and Co 2+ The change in the amount of a substance over time. + and Co 2+ The dissolution amount of α-glucose and β-glucose was very small, and the dissolution rates were 35 and 26 μmol·h -1 ·g -1 .like Figure 14 As shown in the middle right figure, after 4 hours of light exposure, Li + and Co 2+ The recovery rates (dissolution efficiencies) were 0.8% and 0.6%, respectively.

[0147] Comparative Example 2

[0148] A method for recycling positive electrode materials of light-driven lithium-ion batteries comprises the following steps:

[0149] System solution preparation: T1 photocatalyst (30 mg) and LiCoO2 (50 mg) were added to 0.2 M acetic acid aqueous solution (15 mL) and ultrasonically dispersed for 10 minutes.

[0150] Oxygen was introduced into the system, and the reactor was sealed. The system was irradiated with a 300 W xenon lamp light source, and the light intensity was adjusted to 500 mW·cm using a Fresnel lens. -2 The range is to maintain the water phase temperature at around 80 °C, and metal ions are gradually leached from the positive electrode material of the lithium-ion battery.

[0151] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 15 As shown, Figure 15 The middle left figure shows the average amount of Li that can be leached per gram of photocatalyst within 4 hours of illumination. + and Co 2+ The change in the amount of a substance over time. + and Co 2+ The dissolution amount of α-amylase and α-amylase increased linearly with the illumination time, and the dissolution rates reached 1057 and 1055 μmol·h, respectively. -1 ·g -1 .like Figure 15 As shown in the middle right figure, after 4 hours of light exposure, Li + and Co 2+ The recoveries (dissolution efficiencies) were 35.4% and 24.8%, respectively.

[0152] Comparative Example 3

[0153] A method for recycling positive electrode materials of light-driven lithium-ion batteries comprises the following steps:

[0154] Oil phase preparation: The photocatalyst (30 mg) shown in structure T1 was dispersed in n-octanol (15 mL) and ultrasonically dispersed for 10 minutes to form a uniformly dispersed suspension.

[0155] Aqueous phase preparation: LiCoO2 (50 mg) was added to 0.2 M acetic acid aqueous solution (15 mL) with an oil / water volume ratio of 1:1.

[0156] Argon was introduced into the system and the reactor was sealed. A 300 W xenon lamp was used for irradiation. The light intensity was adjusted to 500 mW·cm using a Fresnel lens. -2 The range is to maintain the water phase temperature at around 80 °C, and metal ions are gradually leached from the positive electrode material of the lithium-ion battery.

[0157] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the LiCoO2 was analyzed by inductively coupled plasma emission spectrometry. + and Co 2+ Quantitative detection of content, the test results are as follows Figure 16 As shown, Figure 16The middle left figure shows the average amount of Li that can be leached per gram of photocatalyst within 4 hours of illumination. + and Co 2+ The amount of a substance changes with time. + and Co 2+ The dissolution amount of α-amylase increased linearly with the illumination time, but the dissolution rate was slow, which was 294 and 128 μmol·h -1 ·g -1 .like Figure 16 As shown in the middle right figure, after 4 hours of light exposure, Li + and Co 2+ The recovery rates (dissolution efficiency) of 1, 2, 3 and 4 were only 6.9% and 3%, respectively.

[0158] Test Example 1

[0159] To verify the long-term operational stability of the water / oil two-phase light-driven recycling system, a continuous cycle experiment was conducted. The reaction conditions were the same as in Example 1. After every four hours, the lower aqueous phase was removed and replaced with LiCoO2 (50 mg) and 0.2 M acetic acid aqueous solution (15 mL).

[0160] Figure 17 The experimental results of the cyclic stability test show that the metal ion dissolution rate of the water / oil two-phase light-driven recycling system showed no significant decrease after six cycles (a total of 24 hours of reaction), demonstrating the excellent stability of the water / oil two-phase light-driven recycling system. The excellent stability of the water / oil two-phase light-driven recycling system is mainly due to the following factors: 1. The n-octanol oil phase can act as a hole sacrificial agent, not only accelerating the oxygen reduction to produce H2O2, but also effectively inhibiting the self-oxidation of the catalyst; 2. The establishment of the two-phase interface enables the in situ generated H2O2 to migrate rapidly and directed to the aqueous phase, where it then participates in the decomposition reaction of LiCoO2, preventing the photocatalyst from being continuously exposed to H2O2 and reactive oxygen species, thereby further reducing the risk of photocatalyst degradation. 3. The use of a rigid, irreversible benzobisoxazole structure as a linking unit in the photocatalyst molecular structure greatly improves its chemical stability in elevated temperatures and acidic media.

[0161] Test Example 2

[0162] Based on the feasibility of laboratory scale, an outdoor amplification experimental system based on natural sunlight was constructed. The outdoor experimental device is as follows: Figure 18 As shown in a, the enlarged image is as follows Figure 18 (b) In outdoor experiments, a 70 cm × 70 cm square Fresnel lens was used to focus sunlight, ensuring that the spot covered the entire reactor. The angle and distance between the lens and the reactor were continuously adjusted according to the sun's position to control light intensity and reaction temperature.

[0163] The outdoor experiment was amplified 20 times compared to the laboratory reaction conditions. The specific reaction conditions are as follows:

[0164] Oil phase preparation: T1 photocatalyst (600 mg) was dispersed in n-octanol (300 mL) and ultrasonicated to form a uniform dispersion system;

[0165] Aqueous phase preparation: LiCoO2 (1 g) was dispersed in 0.6 M acetic acid aqueous solution (300 mL) with an oil / water volume ratio of 1:1.

[0166] After the water and oil phases are placed in the reactor, they are sealed and placed outdoors in an air atmosphere. This device can save energy consumption of artificial light sources and heating devices. It is also equipped with a peristaltic pump (flow rate 0.5-50 mL·min -1 Adjustable) to achieve timely product separation and raw material replenishment. The precipitated metal ion solution in the lower layer can be discharged to a storage tank in real time, and fresh acetic acid solution in the lower layer can be continuously fed into the reaction. Temperature, natural light intensity, and focused light intensity are recorded in real time using a thermometer and light intensity meter.

[0167] During the reaction, the aqueous phase sample (0.15 mL) was taken every hour and filtered through a 0.22 μm needle filter to remove solid particles (unreacted LiCoO2). After a certain proportion of dilution, the LiCoO2 was analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). + and Co 2+ Quantitative detection of content, the test results are as follows Figure 19 As shown, under the full sunlight irradiation condition, Li + With Co 2+ The cumulative dissolution amounts of 10371.7 and 9472.5 μmol, respectively, and the corresponding dissolution rates were 1482 and 1353 μmol·h -1 The metal ion dissolution rate showed a strong positive correlation with the sunlight intensity. When the initial light intensity was 30-60 mW·cm -2 During the startup phase (09:00-12:00), Li + With Co 2+ The dissolution rates were stable at ~2200 μmol·h -1 With ~2000 μmol·h -1 When the sunlight intensity gradually decreases to 20-50 mW·cm -2 During the period (13:00-15:00), Li + With Co 2+ The average dissolution rate can only reach ~600 μmol·h -1 During 15:00-16:00, the metal ion dissolution rate was almost zero.

[0168] The solar-driven outdoor system has shown excellent long-term operational stability and practical application prospects. A 30-day outdoor empirical study was conducted, and the research results are as follows: Figure 20 As shown in the figure, it is proved that the recovery efficiency of metal ions in the system remains stable during the complete experimental period including 4 cloudy days. + and Co 2+ The average daily dissolution amount of α-aminobutyric acid and α-aminobutyric acid reached 8.7 mmol and 8.4 mmol respectively. It is worth noting that even on the 7th day with the lowest light intensity during the experiment (cloudy weather, average temperature 8 ℃, and average daily solar intensity of only 30 mW·cm -2 ), the system still maintained a dissolution efficiency of approximately 60%. The system's continuous and stable operation enabled the recovery of high-value metal ions from lithium-ion batteries entirely powered by solar energy. This technological breakthrough demonstrates the feasibility of efficiently recycling discarded batteries using solar energy as a single energy source.

[0169] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for recycling positive electrode materials of light-driven lithium-ion batteries, characterized in that: The following steps are involved: A water / oil two-phase light-driven recovery system is constructed, in which a photocatalyst is dispersed in an upper oil phase, and a lithium-ion battery cathode material and acid are dispersed in a lower water phase. The water / oil two-phase light-driven recovery system is irradiated with light in an oxygen or air atmosphere to drive a catalytic reaction, causing metal ions to leach from the lithium-ion battery cathode material, and then chemical precipitation is used to recover the metal ions. The photocatalyst is selected from one or more of the following T1-T3 structures: 、 、 ； The oil phase is a non-water-soluble alcohol solvent with a density lower than that of water and a boiling point greater than 100°C.

2. The method according to claim 1, wherein The photocatalyst is obtained by reacting an aldehyde monomer and an amino monomer in an organic solvent at 80-150°C; The aldehyde monomer is 2,3,6,7,10,11-hexa(4-formylphenyl)triphenylene, and the amine monomer is 2,5-diamino-1,4-benzodithiophene dihydrochloride, 2,5-diamino-1,4-dihydroxybenzene dihydrochloride or 1,2,4,5-benzenetetramine tetrahydrochloride.

3. The method according to claim 1, wherein The concentration of the photocatalyst in the oil phase is 0.1-100 g / L.

4. The method according to claim 1, wherein The positive electrode material of the lithium ion battery is selected from LiCoO2, LiFePO4, LiCo x Ni y Mn 1-x-y One or more of O2, LiMn2O4, LiNiCoAlO2, LiV2O4, Li2FeTiO4; wherein, 0 <x,0<y,x+y<1。 5. The method according to claim 1, wherein The concentration of the lithium-ion battery positive electrode material in the aqueous phase is 0.1-100 g / L.

6. The method according to claim 1, characterized in that The acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, formic acid, acetic acid, citric acid, maleic acid, malic acid and ascorbic acid.

7. The method according to claim 1, wherein The concentration of the acid in the aqueous phase is 0.05-5 M.

8. The method according to claim 1, characterized in that The volume ratio of the oil phase to the water phase is (0.1-10):1.

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