A lithium recovery method based on weakly polar organic solvents and its application

Abstract

This invention provides a lithium recovery method based on a weakly polar organic solvent and its application, belonging to the field of waste battery recycling. The method includes the following steps: leaching the negative electrode material of a waste lithium-ion battery using a lithium extraction reagent to obtain a solid-liquid mixture. The lithium extraction reagent includes aromatic compounds and a weakly polar organic solvent for dissolving the aromatic compounds. The weakly polar organic solvent can retain the electron-withdrawing effect of the large π bond in the aromatic compounds, thereby increasing the lithium leaching rate. The obtained solid-liquid mixture is then separated to obtain a lithium-rich solution, thus achieving efficient lithium recovery from waste lithium-ion batteries. This invention uses a weakly polar solvent to dissolve the aromatic compounds. Due to the weak Lewis basicity of the solvent, the electron-withdrawing effect of the large π bond in the aromatic compounds can be retained, ensuring a strong interaction between the solvent and the elemental lithium in the negative electrode material, significantly improving the lithium leaching rate and lithium extraction efficiency.

Description

Technical Field

[0001] This invention belongs to the field of waste battery recycling, and more specifically, relates to a lithium recycling method based on a weakly polar organic solvent and its application. Background Technology

[0002] In the electrodes of lithium-ion batteries, lithium exists as elemental lithium rather than lithium ions. Solvents can only react with lithium ions and cannot directly react with elemental lithium. Therefore, solvents cannot directly extract elemental lithium from the negative electrode. Instead, they can extract elemental lithium from the negative electrode by reacting with the large π bonds contained in polycyclic aromatic hydrocarbons.

[0003] In the prior art, CN113061726B discloses a method for safely and efficiently recovering lithium from waste batteries. This method involves directly immersing the negative electrode material in an organic reagent containing polycyclic aromatic hydrocarbons (PAHs) to obtain a lithium-rich solution. It uses a strongly polar solvent to dissolve the PAHs; however, this strongly polar solvent is a Lewis base and readily interacts with the large π bonds of the PAHs, weakening the electron-withdrawing effect of the large π bonds. This weakens the interaction between the large π bonds and the elemental lithium in the negative electrode, thus reducing the lithium extraction rate and the amount of lithium that can be extracted per unit volume of solvent. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a lithium recovery method based on weakly polar organic solvents and its application, thereby solving the problem that existing lithium recovery methods use strongly polar solvents to dissolve multiple aromatic hydrocarbons, resulting in a reduced lithium extraction rate.

[0005] To achieve the above objectives, according to one aspect of the present invention, a lithium recovery method based on a weakly polar organic solvent is provided, the method comprising the following steps:

[0006] S1 uses a lithium extraction reagent to leach the negative electrode material of a waste lithium-ion battery to obtain a solid-liquid mixture. The lithium extraction reagent includes aromatic compounds and a weakly polar organic solvent for dissolving the aromatic compounds. The weakly polar organic solvent can retain the electron-withdrawing effect of the large π bond of the aromatic compounds, thereby improving the leaching rate and efficiency of lithium.

[0007] S2 separates the solid-liquid mixture obtained in step S1 to obtain a lithium-rich solution, thereby achieving efficient recovery of lithium from spent lithium-ion batteries.

[0008] As a further preferred embodiment, in step S1, ultrasound is used to assist in leaching to further improve the leaching rate and efficiency of lithium.

[0009] As a further preferred embodiment, in step S1, the power of the ultrasound is 300W to 3000W.

[0010] As a further preferred embodiment, the weakly polar organic solvent is an organic solvent with a dielectric constant less than 7, specifically including tetrahydrofuran containing 1 to 3 substituents, tetrahydropyran containing 1 to 3 substituents, ethers containing 2 ether bonds and at least 5 carbons and substituents, diethyl ether, dimethoxymethane, 1,4-dioxane, 2-ethoxy-4-(trifluoromethyl)-1,3-dioxane, 2-ethoxy-4-(trifluoromethyl)-1,3-dioxane, cyclopentyl methyl ether, hexafluoroisopropyl methyl ether, and bis(2,3-dioxane). One or more of 2,2-trifluoroethyl ether, 1,1,1,3,3,3-hexafluoroisopropylmethyl ether, 1,1,2,2-tetrafluoroethyl ether-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and tris(2,2,2)-trifluoroethyl orthoformate, wherein the substituent is one or more of alkyl, hydroxyl, nitro, halogen, amino, carboxyl, aldehyde, and carbonyl groups.

[0011] As a further preferred embodiment, the aromatic compound has 10 to 30 carbon atoms and has 2 to 4 benzene rings, specifically including one or more of biphenyl, naphthalene, phenanthrene, anthracene, tetraphenyl, pyrene, and perylene; the aromatic compound has 1 to 4 substituents, the substituents being one or more of alkyl, hydroxyl, nitro, halogen, amino, carboxyl, aldehyde, and carbonyl groups.

[0012] As a further preferred embodiment, the concentration of aromatic compounds in the lithium extraction reagent is 0.01 mol / L to 7 mol / L, preferably 0.5 mol / L to 2 mol / L.

[0013] As a further preferred embodiment, the leaching temperature is 20℃~80℃, preferably 20℃~60℃, and the leaching time is 2h~10h.

[0014] As a further preferred embodiment, the molar ratio of lithium in the negative electrode material to the aromatic compounds in the lithium extraction reagent is 1:1 to 1:3.

[0015] According to another aspect of the present invention, a lithium recovery and utilization method based on a weakly polar organic solvent is provided. The method uses the above-mentioned lithium recovery method based on a weakly polar organic solvent to obtain a lithium-rich solution, and then uses the lithium-rich solution to soak the material to be treated to achieve lithium recovery and utilization. The material to be treated includes one or more of waste positive electrode materials, new negative electrode materials, and high specific capacity lithium-free positive electrode materials, thereby realizing the regeneration of waste positive electrode materials, the pre-physicochemical treatment of new negative electrode materials, and the replenishment of lithium to high specific capacity lithium-free positive electrode materials.

[0016] As a further preferred embodiment, the lithium recycling method based on weakly polar organic solvents further includes calcining the recycled waste cathode material at 500℃ to 1000℃ for 1h to 24h to remove the binder and restore the internal structure.

[0017] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0018] 1. This invention uses a weakly polar solvent to dissolve aromatic compounds. Due to the weak Lewis basicity of the solvent, the electron-withdrawing effect of the large π bond of the aromatic compounds can be preserved, thereby ensuring that they have a strong interaction with the elemental lithium in the negative electrode material. This not only significantly improves the lithium leaching rate, but also greatly increases the lithium content extracted from the aromatic compounds per unit volume of solvent, thereby increasing the lithium extraction efficiency.

[0019] 2. In particular, the present invention proposes to use ultrasonic-assisted leaching, which can destroy the passivation film on the surface of the negative electrode material, promote the peeling of graphite from the current collector, and make it more conducive to the uniform mixing of lithium extraction reagent and lithium-containing graphite, thereby accelerating lithium leaching and further improving the lithium leaching rate and efficiency.

[0020] 3. In addition, this invention also optimizes the types and concentrations of weak organic solvents and aromatic compounds, which can accelerate the extraction efficiency and dissolution rate of lithium and save time and costs;

[0021] 4. In addition, this invention proposes to directly use lithium-rich solutions for the regeneration of waste cathode materials, the pre-physicochemical treatment of new anode materials, and the lithium replenishment of high-specific-capacity lithium-free cathode materials, thereby enabling the rapid and convenient reuse of recycled lithium, which greatly enriches existing battery manufacturing technologies. Attached Figure Description

[0022] Figure 1 This is a flowchart of lithium recovery based on weakly polar organic solvents provided in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] like Figure 1 As shown, according to one aspect of the present invention, a lithium recovery method based on a weakly polar organic solvent is provided, the method comprising the following steps:

[0025] S1 uses a lithium extraction reagent to leach the negative electrode material of a spent lithium-ion battery to obtain a solid-liquid mixture. The lithium extraction reagent includes aromatic compounds and a weakly polar organic solvent for dissolving the aromatic compounds. The weakly polar organic solvent has a weaker interaction with the aromatic compounds and can retain the electron-withdrawing effect of the large π bond of the aromatic compounds, thereby ensuring that it has a strong interaction with the elemental lithium in the negative electrode material, which is beneficial to the leaching of lithium in the negative electrode and the improvement of efficiency.

[0026] S2 separates the solid-liquid mixture obtained in step S1 to obtain a lithium-rich solution, thereby achieving efficient recovery of lithium from waste lithium-ion batteries.

[0027] S3 uses a lithium-rich solution to soak waste positive electrode materials and brand-new negative electrode materials to remove impurities, thereby achieving the regeneration of waste positive electrode materials and the pre-physicochemical treatment of negative electrode materials.

[0028] Furthermore, in step S1, ultrasound is used to assist in leaching. Ultrasound breaks the passivation film on the surface of the negative electrode material, promotes the peeling of graphite from the current collector, and facilitates the uniform mixing of lithium extraction reagent and lithium-containing graphite, thereby accelerating lithium leaching and further improving the lithium leaching rate and efficiency. The ultrasonic power is preferably 300W to 3000W.

[0029] Furthermore, the method for obtaining the negative electrode material of waste lithium-ion batteries is as follows: the waste lithium-ion batteries are charged to 100% SOC with a small current, and then disassembled and sorted to obtain the negative electrode sheets in a safe environment with a dew point of less than -50°C. The negative electrode sheets include, but are not limited to, lithium metal negative electrodes, carbon-based active materials, and silicon-based active materials. Among them, carbon-based active materials include, but are not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, and mesophase carbon microspheres, and silicon-based active materials include, but are not limited to, one or more of elemental silicon, silicon alloys, and silicon suboxide.

[0030] Furthermore, the weakly polar organic solvent is one or more of the following organic solvents with a dielectric constant of less than 7: ethers, esters, and aromatics. Preferably, it is one or more of the following organic solvents: ethers and esters with a dielectric constant of less than 7, including but not limited to tetrahydrofuran containing 1-3 substituents, tetrahydropyran containing 1-3 substituents, ethers containing 2 ether bonds and at least 5 carbons and substituents, diethyl ether, dimethoxymethane, 1,4-dioxane, 2-ethoxy-4-(trifluoromethyl)-1,3-dioxane, and 2-ethoxy-4-(trifluoromethyl)-1,3-dioxane. One or more of the following: pentane, cyclopentyl methyl ether, hexafluoroisopropyl methyl ether, bis(2,2,2-trifluoroethyl) ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether, 1,1,2,2-tetrafluoroethyl ether-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and tri(2,2,2-trifluoroethyl) orthoformate, wherein the substituent is one or more of the following: alkyl, hydroxyl, nitro, halogen, amino, carboxyl, aldehyde, and carbonyl.

[0031] Aromatic compounds have 10 to 30 carbon atoms and 2 to 4 benzene rings, specifically selected from one or more of biphenyl, naphthalene, phenanthrene, anthracene, tetraphenyl, pyrene, and perylene. Aromatic compounds have 1 to 4 substituents, which are one or more of alkyl (1 to 5 carbon atoms, such as methyl, ethyl, propyl, butyl), hydroxyl, nitro, halogen (F, Cl, Br, I), amino, carboxyl, aldehyde, and carbonyl groups.

[0032] Furthermore, the concentration of aromatic compounds in the lithium extraction reagent is 0.01 mol / L to 7 mol / L, preferably 0.5 mol / L to 2 mol / L. By optimizing the concentration of aromatic compounds in the lithium extraction reagent, it is possible to avoid excessive concentration leading to increased solution viscosity, which would result in poor wettability to the electrode and thus reduce lithium extraction efficiency. At the same time, it is also possible to avoid excessively low concentration, which would make it difficult to extract enough lithium per unit volume of solution and thus waste solvent.

[0033] Furthermore, in step S1, the leaching temperature is 20℃~80℃, preferably 20℃~60℃, and the leaching time is 2h~10h. At the same time, the molar ratio of lithium in the negative electrode material to the aromatic compounds in the lithium extraction reagent is 1:1~1:3, thereby ensuring that there are enough aromatics to react with lithium and to extract the active lithium in the negative electrode as completely as possible.

[0034] According to another aspect of the present invention, a lithium recycling method based on a weakly polar organic solvent is provided. This method uses the above-mentioned lithium recycling method based on a weakly polar organic solvent to obtain a lithium-rich solution, and then uses the lithium-rich solution to soak the material to be treated to achieve lithium recycling. The material to be treated includes one or more of waste cathode materials, brand-new anode materials, and high specific-capacity lithium-free cathode materials, thereby realizing the regeneration of waste cathode materials, the pre-physical treatment of brand-new anode materials, and the lithium supplementation of high specific-capacity lithium-free cathode materials.

[0035] Furthermore, the waste cathode materials include layered cathode materials, spinel-type cathode materials, olivine-type cathode materials, and the corresponding doped and modified cathode materials, specifically including but not limited to Li x CoO2, Li x FePO4, Li x Mn2O4, Li x Ni y Co z Mn I O2(y + z + I = 1), LiNi y Co z Al I O2(y + z + I = 1), Li x NiO2, Li x VO2, Li x CrO2, Li x CoMnO4, Li x NiMn3O8, Li x Ni 0.5 Mn 1.5 O4(0 < x < 1), and one or more of them. The brand-new anode materials include but not limited to carbon-based materials, silicon-based materials, tin-based materials, phosphorus-containing materials, sulfur-containing materials, and lithium titanate. Among them, the carbon-based materials include one or more of natural graphite, artificial graphite, soft carbon, hard carbon, and mesocarbon microbeads. The silicon-based materials include one or more of silicon单质, silicon alloy, and silicon monoxide. The high specific-capacity lithium-free cathode materials include but not limited to sulfur单质, metal fluorides, metal oxides, and metal sulfides, and one or more of them.

[0036] Meanwhile, the washed and regenerated waste cathode materials can also be calcined to remove the binder inside the materials and restore the material structure. The calcination temperature is 500°C to 1000°C, preferably 800°C to 1000°C, the calcination time is 1h to 24h, and the calcination atmosphere includes argon, nitrogen, or oxygen.

[0037] The following further illustrates the technical solutions provided by the present invention according to specific embodiments.

[0038] Example 1

[0039] (a) The waste nickel-cobalt-manganese ternary lithium battery was charged to 4.3V using constant current charging, and then charged again with constant voltage until the charging current density dropped to 10% of the initial constant current charging current density, the voltage remained stable, and charging was stopped.

[0040] (b) Disassemble the waste nickel-cobalt-manganese ternary lithium battery in an environment with a dew point of -50°C, remove the negative electrode sheet, and cut it to a suitable size;

[0041] (c) Prepare lithium extraction reagent: Add 15.4 g of biphenyl and 100 ml of methyltetrahydrofuran solvent to a beaker and stir until a homogeneous solution is formed (the concentration of biphenyl is 1 mol / L).

[0042] (d) The cut negative electrode sheet is placed in the lithium extraction reagent. The leaching temperature is room temperature. The molar ratio of lithium in the negative electrode material to the molar ratio of aromatic compounds in the lithium extraction reagent is 1:3. The leaching time is 2 hours and the leaching temperature is 30℃. After leaching, the solution is filtered to obtain a lithium-rich solution.

[0043] Example 2

[0044] Same as in Example 1, except that the solvent in the lithium extraction reagent is 2,5-dimethyltetrahydrofuran.

[0045] Example 3

[0046] Same as in Example 2, the concentration of biphenyl was 0.01 mol / L.

[0047] Example 4

[0048] Same as in Example 2, the concentration of biphenyl is 0.5 mol / L.

[0049] Example 5

[0050] Same as in Example 2, the concentration of biphenyl is 7 mol / L.

[0051] Example 6

[0052] Same as Example 1, except that the solute in the lithium extraction reagent is naphthalene and the leaching temperature is 20°C.

[0053] Example 7

[0054] Same as Example 6, except the leaching temperature is 60°C.

[0055] Example 8

[0056] Same as Example 6, except the leaching temperature is 80°C.

[0057] Example 9

[0058] Same as Example 1, except that the solute in the lithium extraction reagent is pyrene.

[0059] Example 10

[0060] Same as Example 9, except the leaching time is 5 hours.

[0061] Example 11

[0062] Same as Example 9, except the leaching time is 10 hours.

[0063] Example 12

[0064] Same as Example 11, except that the molar ratio of lithium in the negative electrode material to the aromatic compounds in the lithium extraction reagent is 1:1.

[0065] Example 13

[0066] Same as Example 1, except that the solute in the lithium extraction reagent is anthracene.

[0067] Example 14

[0068] Same as in Example 13, except that the concentration of anthracene in the lithium extraction reagent is 1.5 mol / L and the solvent is diethyltetrahydrofuran.

[0069] Example 15

[0070] Same as Example 13, except that the concentration of anthracene in the lithium extraction reagent is 2 mol / L and the solvent is 2,5-dimethyltetrahydrofuran.

[0071] Comparative Example 1

[0072] Same as Example 1, except that the solvent in the lithium extraction reagent is tetrahydrofuran (a strongly polar organic solvent).

[0073] Comparative Example 2

[0074] Same as Example 1, except that the solvent in the lithium extraction reagent is ethylene glycol dimethyl ether (a highly polar organic solvent).

[0075] The utilization rate of the lithium extraction agent was determined based on the lithium extraction efficiency. Table 1 shows the reaction conditions and lithium extraction efficiencies of Examples 1-15 and Comparative Examples 1-2. It can be seen that the use of a weakly polar organic solvent in this invention can effectively leverage the interaction between the large π bond of aromatic compounds and elemental lithium, thereby achieving higher lithium extraction efficiency.

[0076] Table 1. Reaction conditions and lithium extraction efficiency of Examples 1-15 and Comparative Examples 1-2

[0077]

[0078]

[0079] The lithium-rich solution obtained in Example 1 was soaked with recycled waste cathode materials, including lithium iron phosphate, lithium cobalt oxide, lithium nickel manganese oxide, and lithium manganese oxide. After centrifugation and washing, regenerated waste cathode materials were obtained. The regenerated waste cathode materials were mixed with Super P and polyvinylidene fluoride binder at a mass ratio of 80:10:10 to form a slurry, which was uniformly coated onto an aluminum foil current collector as the counter electrode. The slurry was then assembled into a 2032 coin cell in a glove box. The separator used was polypropylene (purchased from Celgard, USA), and the electrolyte was a commercially available lithium hexafluorophosphate electrolyte with a specific formulation of 1M LiPF6-EC / EMC (volume ratio 3:7). The assembled battery was tested for charge and discharge on a Newway charge and discharge tester, and the test results are shown in Table 2. It can be seen that the initial capacity of the waste cathode materials treated with the lithium-rich solution can be restored to 98% of that of brand-new cathode materials, and the capacity retention rate of the materials after 1000 cycles is as high as 95%, which is comparable to the stability of brand-new cathode materials.

[0080] Table 2. Test results of batteries assembled from recycled waste cathode materials.

[0081]

[0082]

[0083] The lithium-rich solution obtained in Example 2 was soaked with novel negative electrode materials, including graphite, silicon negative electrode, phosphorus negative electrode, and hard carbon. After centrifugation and washing, pre-lithiated negative electrode materials were obtained. The pre-lithiated negative electrode materials, Super P, and sodium carboxymethyl cellulose binder were mixed at a mass ratio of 80:10:10 to form a slurry, which was uniformly coated onto a copper foil current collector to obtain a working electrode. The cells were assembled into 2032 coin cells in a glove box. The separator used was polypropylene (purchased from Celgard, USA), and the electrolyte was a commercial lithium hexafluorophosphide electrolyte with a specific formulation of 1M LiPF6-EC / EMC (volume ratio 3:7). The assembled cells were tested for charge and discharge on a Newway charge and discharge tester. At the same time, the untreated enriched materials were assembled into cells for testing. The test results are shown in Table 3. It can be seen that the initial coulombic efficiency of the new anode materials pretreated with lithium-rich solution was significantly improved. Specifically, the initial coulombic efficiency of graphite anode increased from 85% to 99%, silicon anode from 70% to 100%, phosphorus anode from 75% to 98%, and hard carbon anode from 70% to 100%.

[0084] Table 3 Test results of batteries assembled with pre-treated negative electrode materials

[0085]

[0086] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lithium recovery method based on a weakly polar organic solvent, characterized in that, The method includes the following steps: S1 utilizes a lithium extraction reagent to leach the negative electrode material of spent lithium-ion batteries to obtain a solid-liquid mixture. The lithium extraction reagent comprises aromatic compounds and a weakly polar organic solvent for dissolving the aromatic compounds. This weakly polar organic solvent retains the electron-withdrawing effect of the large π bond in the aromatic compounds, thereby improving the lithium leaching rate and efficiency. The weakly polar organic solvent is an organic solvent with a dielectric constant less than 7, specifically including tetrahydrofuran containing 1-3 substituents, tetrahydropyran containing 1-3 substituents, ethers containing 2 ether bonds and at least 5 carbons and substituents, diethyl ether, dimethoxymethane, 1,4-dioxane, and 2-ethoxy-4-(trifluoromethyl)- One or more of 1,3-dioxolane, 2-ethoxy-4-(trifluoromethyl)-1,3-dioxolane, cyclopentyl methyl ether, hexafluoroisopropyl methyl ether, bis2,2,2-trifluoroethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether, 1,1,2,2-tetrafluoroethyl ether-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and tris2,2,2-trifluoroethyl orthoformate, wherein the substituent is one or more of alkyl, hydroxyl, nitro, halogen, amino, carboxyl, aldehyde, and carbonyl groups; S2 separates the solid-liquid mixture obtained in step S1 to obtain a lithium-rich solution, thereby achieving efficient recovery of lithium from spent lithium-ion batteries.

2. The lithium recovery method based on a weakly polar organic solvent as described in claim 1, characterized in that, In step S1, ultrasound is used to assist in leaching to further improve the leaching rate and efficiency of lithium.

3. The lithium recovery method based on a weakly polar organic solvent as described in claim 2, characterized in that, In step S1, the power of the ultrasound is 300W to 3000W.

4. The lithium recovery method based on a weakly polar organic solvent as described in claim 1, characterized in that, The aromatic compounds have 10 to 30 carbon atoms and 2 to 4 benzene rings, specifically including one or more of biphenyl, naphthalene, phenanthrene, anthracene, tetraphenyl, pyrene, and perylene; the aromatic compounds have 1 to 4 substituents, the substituents being one or more of alkyl, hydroxyl, nitro, halogen, amino, carboxyl, aldehyde, and carbonyl groups.

5. The lithium recovery method based on a weakly polar organic solvent as described in claim 1, characterized in that, The concentration of aromatic compounds in the lithium extraction reagent is 0.01 mol / L to 7 mol / L.

6. The lithium recovery method based on a weakly polar organic solvent as described in claim 5, characterized in that, The concentration of aromatic compounds in the lithium extraction reagent is 0.5 mol / L to 2 mol / L.

7. The lithium recovery method based on a weakly polar organic solvent as described in claim 1, characterized in that, The leaching temperature is 20℃~80℃, and the leaching time is 2 h~10 h.

8. The lithium recovery method based on a weakly polar organic solvent as described in claim 7, characterized in that, The leaching temperature is 20℃~60℃.

9. The lithium recovery method based on a weakly polar organic solvent as described in claim 1, characterized in that, The molar ratio of lithium in the negative electrode material to the aromatic compounds in the lithium extraction reagent is 1:1 to 1:

3.

10. A method for lithium recovery and utilization based on a weakly polar organic solvent, characterized in that, The method uses the lithium recovery method based on weakly polar organic solvents as described in any one of claims 1 to 9 to obtain a lithium-rich solution, and then uses the lithium-rich solution to soak the material to be treated to achieve lithium recovery and utilization. The material to be treated includes one or more of waste positive electrode materials, new negative electrode materials, and high specific capacity lithium-free positive electrode materials, thereby realizing the regeneration of waste positive electrode materials, the pre-physicochemical treatment of new negative electrode materials, and the replenishment of lithium to high specific capacity lithium-free positive electrode materials.

11. The lithium recovery and utilization method based on a weakly polar organic solvent as described in claim 10, characterized in that, The lithium recycling method also includes calcining the recycled waste cathode material at 500℃~1000℃ for 1h~24h to remove the binder and restore the internal structure.

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