Molten salt electrochemical driving full-reconstruction recovery method of waste lithium ion battery positive electrode material

Abstract

The invention provides a molten salt electrochemical driving full-reconstruction recovery method for a waste lithium ion battery positive electrode material. The method comprises the following steps: 1) disassembling a waste lithium ion battery to obtain a waste aluminum foil and a waste positive electrode material; 2) taking the waste aluminum foil as a negative electrode, taking a waste positive electrode material as a positive electrode, and assembling the negative electrode, the positive electrode, an alkaline molten salt electrolyte and a diaphragm to obtain a molten salt aluminum battery; 3) carrying out a complete discharge step on the molten salt aluminum battery, and then disassembling to obtain a discharge product; and 4) washing and filtering the discharge product, collecting the filtrate to obtain a LiCl solution, and pickling the filter residue to obtain a metal chloride solution and a solid Al2O3. Through a simple molten salt electrochemical method, complete reconstruction and recovery of the positive electrode material of the waste lithium ion battery can be achieved, a high-value final product is obtained, and the method has the advantages of being high in universality, simple in process, environmentally friendly, low in cost and high in recovery rate and has a large-scale application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of regeneration of useful parts of waste batteries, and in particular relates to a molten salt electrochemical driven full reconstruction recovery method for positive electrode materials of waste lithium-ion batteries. Background Art

[0002] Lithium-ion batteries (LiBs) have unique advantages such as high energy density, strong stability and long life. They are widely used in our lives, such as electric vehicles, energy storage and other fields, and will continue to grow in the foreseeable future. For example, the average service life of lithium-ion batteries in electric vehicles is about 8-10 years. Therefore, a large amount of waste lithium-ion batteries is generated every year. It is predicted that electric vehicles will generate up to 4 million tons of waste lithium-ion batteries in the next 20 years. However, the recycling of waste lithium-ion batteries has high environmental and energy requirements and has long been considered uneconomical and technically challenging.

[0003] Among all the components of waste lithium-ion batteries, the positive electrode material is the most worth recycling. At present, the main methods used by the recycling industry for the recovery of positive electrode materials are molten metallurgy, hydrometallurgy or a combination thereof. However, molten metallurgy relies on a high-energy consumption process with an operating temperature of more than 1400°C; while hydrometallurgy is limited by the use of a large amount of environmentally unfriendly leaching reagents (hydrochloric acid, nitric acid, sulfuric acid, etc.). Current extraction and separation methods still face challenges in terms of energy consumption, environmental issues or recycling efficiency.

[0004] In view of this, the present invention proposes a new method for recycling waste lithium-ion battery positive electrode materials. Compared with traditional recycling methods, the new method has simple process, low energy consumption, small environmental impact and high resource recovery rate, and has an ideal industrialization prospect. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a molten salt electrochemically driven full reconstruction recycling method for waste lithium-ion battery positive electrode materials in view of the above-mentioned deficiencies in the prior art. The method is based on a molten salt electrolyte and uses waste positive electrodes and waste aluminum foil stripped from waste lithium-ion battery positive electrodes as positive and negative electrodes, respectively, to assemble aluminum batteries and perform full discharge. The fully discharged products are simply washed with water and then treated with dilute acid. The waste lithium-ion battery positive electrode materials can be efficiently recycled by full reconstruction. The method has simple process, low cost, high recovery rate and can be used on a large scale, showing an ideal industrialization prospect.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials is provided, comprising the following steps:

[0008] 1) Dismantling the waste lithium-ion batteries and stripping them to obtain waste aluminum foil (positive electrode current collector) and waste positive electrode materials;

[0009] 2) using the waste aluminum foil obtained in step 1) as the negative electrode and the waste positive electrode material obtained in step 1) as the positive electrode, and assembling the negative electrode, the positive electrode, an alkaline molten salt electrolyte and a separator under an inert atmosphere to obtain a molten salt aluminum battery;

[0010] 3) disassembling the molten salt aluminum battery assembled in step 2) after a complete discharge step to obtain a discharge product;

[0011] 4) The discharge product obtained in step 3) is washed with water, filtered, and the filtrate is collected to obtain a LiCl solution, and then the filter residue is immersed in a dilute HCl solution for pickling. The liquid after pickling is a metal chloride solution, and the solid after pickling is Al 2 O 3 The LiCl solution and the metal chloride solution are used to recover metal lithium salts and other metal salts and metal oxides (such as by precipitation filtration).

[0012] According to the above scheme, the waste positive electrode material in step 1) includes LiCoO 2 , one or more of the ternary NCM positive electrode materials and the ternary NCA positive electrode materials.

[0013] According to the above scheme, the alkaline molten salt electrolyte in step 2) is generally formulated as A a AlX b , wherein A is selected from at least two of Ca, Mg, Li, Na, K, Rb and Cs, X includes at least one halogen element (F, Cl, Br and I), 1≤a≤2, 4≤b≤5.

[0014] Preferably, 1.05≤a≤1.4, and 4.05≤b≤4.4.

[0015] According to the above scheme, the assembly method of step 2) is: the positive electrode is in contact with one side of the diaphragm, and the other side of the diaphragm is in contact with the negative electrode, a powdered alkaline molten salt electrolyte is added to the battery structure, and the temperature is heated to a temperature exceeding the melting point of the alkaline molten salt electrolyte to melt the electrolyte and infiltrate the electrodes and the diaphragm, or a liquid alkaline molten salt electrolyte is injected into the battery structure and infiltrates the positive electrode, the diaphragm and the negative electrode to form the core components of the battery, and then packaged to obtain a molten salt aluminum battery.

[0016] According to the above scheme, step 3) discharge is performed at a current density of 5-100 mA / g to 0.01-0.3 V, and the system temperature during the discharge process is 80-300° C. When the discharge capacity of the battery is above 90% of the theoretical capacity at this voltage, it can be considered to be fully discharged.

[0017] According to the above scheme, step 4) the water washing step is to add deionized water and soak for 1-3 times, each time for 10 minutes.

[0018] According to the above scheme, the concentration of the dilute HCl solution in step 4) is 5-20 wt%. The amount of the dilute HCl solution is slightly excessive to fully react with the metal in the filter residue.

[0019] According to the above scheme, the pickling time in step 4) is 10-30 minutes.

[0020] The present invention also includes a molten salt aluminum battery obtained based on waste lithium-ion batteries.

[0021] The preparation method of the molten salt aluminum battery comprises the following steps:

[0022] 1) Dismantling the waste lithium-ion batteries and stripping them to obtain waste aluminum foil (positive electrode current collector) and waste positive electrode materials;

[0023] 2) The waste aluminum foil obtained in step 1) is used as the negative electrode, and the waste positive electrode material obtained in step 1) is used as the positive electrode. Under an inert atmosphere, the negative electrode, the positive electrode, an alkaline molten salt electrolyte and a separator are assembled to obtain a molten salt aluminum battery.

[0024] The present invention utilizes waste positive electrode material LiCoO 2 etc. are assembled into a molten salt aluminum battery. During the complete discharge process of the molten salt aluminum battery, LiCoO 2 Transformed into LiCl and metallic Co, chloroaluminate in the electrolyte transforms into Al 2 O 3 The discharge products mainly include LiCl, amorphous Al 2 O 3 , other metal (Co, Ni) salts and oxides, through the different solubility of discharge products in water and dilute acid, the gradient separation and recovery of products is realized. During the water washing process, LiCl is dissolved in water, and during the acid washing process, other metal salts and oxides are dissolved in acid to obtain metal chloride (CoCl 2 、NiCl 2 ) solution, and Al 2 O 3 The acid-insoluble materials are separated. After the subsequent product is recovered, the positive electrode material is synthesized again. The positive electrode material obtained by testing has good performance, which proves that the present invention can directly convert the waste positive electrode into battery-grade materials through the post-lithiation process.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention can achieve complete reconstruction and recycling of waste lithium-ion battery positive electrode materials through a simple molten salt electrochemical method to obtain high-value final products. Compared with the prior art, both positive and negative electrode materials are derived from waste lithium-ion batteries, and the molten salt, water, dilute acid, etc. used in the process can be recycled (most of the electrolyte after the reaction will remain on the diaphragm at room temperature and can be reused), which has strong universality (applicable to LiCoO 2 , ternary NCM, ternary NCA and other waste lithium-ion battery positive electrode materials), with the advantages of simple process, environmental friendliness, low cost and high recovery rate, and has the prospect of large-scale application.

[0027] 2. The present invention can obtain a single-discharge molten salt aluminum battery based on the positive electrode of waste lithium-ion batteries and a molten salt electrolyte, which has the advantages of simple operation, short process flow and suitability for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the recycling process of waste positive electrode materials in Example 1 of the present invention;

[0029] Figure 2 The discharge curve of the molten salt aluminum battery discharge step in step (3) of Example 1;

[0030] Figure 3 The XRD pattern of the discharged product obtained in step (3) of Example 1;

[0031] Figure 4 This is a comparison diagram of the hysteresis loops of the positive electrode material before and after discharge in Example 1;

[0032] Figure 5 TEM image of the discharged product obtained in step (3) of Example 1;

[0033] Figure 6 HRTEM and SAED test images of the discharged product obtained in step (3) of Example 1;

[0034] Figure 7 This is the energy spectrum of the solid product obtained in step (3) of Example 1;

[0035] Figure 8 The discharge curve of the molten salt aluminum battery discharge process in step (3) of Example 2 and the XRD diagram of the discharged product obtained in step (3);

[0036] Fig. 9 The discharge curve of the molten salt aluminum battery discharge step in step (3) of Example 3 and the XRD diagram of the discharged product obtained in step (3). DETAILED DESCRIPTION

[0037] In order to make those skilled in the art better understand the technical scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings, but it should be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If specific conditions are not specified in the examples, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0038] Example 1

[0039] A molten salt electrochemical driven full reconstruction recycling method for waste lithium-ion battery positive electrode materials, the process flow diagram is as follows Figure 1 As shown, the following steps are included:

[0040] (1) Recycling of waste LiCoO 2 The soft-pack battery was disassembled and the waste positive electrode sheet (60 mg, the main component of which is LiCoO 2 ) and aluminum foil;

[0041] (2) Waste positive electrode sheets and aluminum foil are used as positive and negative electrodes respectively, glass fiber separators are used as battery separators, the diameters of the positive and negative electrode sheets and separators are 12 mm, and alkaline molten salt electrolytes are used as battery electrolytes (the specific preparation method of the molten salt electrolyte comprises the following steps: AlCl 3 , NaCl, LiCl and KCl were weighed in a molar ratio of 0.95:0.43:0.42:0.15, added into a sealed container, transferred into an oven, and kept at 160°C for 24 hours to mix the components evenly and completely liquefy. After cooling, they were ground into powder to obtain a molten salt electrolyte with the general formula of Li 0.44 Na 0.45 K 0.16 AlCl 4.05 , melting point is about 130°C), under the protection of inert gas, the positive electrode is contacted with the first surface of the diaphragm, and the second surface of the diaphragm is contacted with the negative electrode, and then a molten salt electrolyte is introduced, and the molten salt electrolyte is contacted with the positive electrode, the diaphragm and the negative electrode to assemble the core components of the molten salt aluminum battery, and then the core components are encapsulated in a Swagelok type sealed structure battery to assemble a molten salt aluminum battery;

[0042] (3) The molten salt aluminum battery obtained in step (2) was completely discharged at a constant current density of 50 mA / g to 0.2 V. The system temperature during the discharge process was 140° C., and then the completely discharged battery was disassembled, and the discharged product (about 100 mg) was completely taken out and soaked and washed with deionized water for 3 times, each time for 10 minutes, and the solid product was filtered and collected. The solid product was solid Al 2 O3 and metal Co, and the washed solution was collected to be a LiCl solution (LiCl content 26 mg, Li recovery rate 99%);

[0043] (4) The solid product (about 75 mg) obtained in step (3) was placed in 20 mL of 10 wt% HCl solution, and the product was filtered and collected after standing for 30 min. The resulting solution was CoCl 2 Solution (Co content 33 mg, Co recovery 94.6%), solid product is Al 2 O 3 (about 40mg).

[0044] Figure 1 This is a schematic diagram of the recycling process of waste positive electrode materials in this embodiment, and a structural change model is demonstrated for the complete reconstruction of waste lithium-ion battery positive electrodes driven by molten salt electrochemistry during the recycling process.

[0045] Figure 2 The discharge curve of the molten salt aluminum battery discharge process step (3) of this embodiment shows that the fine LiCoO 2 The particles can obtain 763mAh g -1 The high capacity of LiCoO is close to the theoretical capacity, which indicates that 2 Completely converted into Co, LiCl and Al 2 O 3 .

[0046] Figure 3 The XRD pattern of the discharged product obtained in step (3) of this embodiment is compared with the standard card, which proves the generation of Co and LiCl, and the absence of LiCoO 2 The characteristic peaks of LiCoO 2 A complete refactoring occurs.

[0047] Figure 4 This is a comparison of the hysteresis loops of the positive electrode material before and after discharge. It can be seen that the non-magnetic lithium cobalt oxide generates magnetic metal after discharge, indicating that the positive electrode material is completely reconstructed during the discharge process.

[0048] Figure 5 This is a TEM image of the discharged product obtained in step (3) of this embodiment. It can be seen that the surface of the product is mainly LiCl with good crystallinity, which also confirms that the positive electrode material is completely reconstructed after discharge.

[0049] Figure 6 The HRTEM and SAED test images of the discharged product obtained in step (3) of this embodiment prove the formation of Co and LiCl in the product.

[0050] Figure 7The energy spectrum of the solid product obtained in step (3) of this embodiment shows that it contains metal Co and amorphous Al. 2 O 3 .

[0051] Example 2

[0052] A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials, comprising the following steps:

[0053] (1) Recycling waste LiNi 0.8 Co 0.1 Mn 0.1 O 2 The soft-pack battery is disassembled and the waste positive electrode material (mainly LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) and aluminum foil;

[0054] (2) The stripped waste positive electrode material and aluminum foil are used as positive and negative electrodes respectively, a glass fiber separator is used as a battery separator, and an alkaline molten salt electrolyte is used (the specific preparation method of the molten salt electrolyte comprises the following steps: under the protection of inert gas, AlCl 3 , NaCl, LiCl and KCl, add them into a container and seal it, transfer it to an oven, keep it at 160°C for 24 hours, mix the components evenly and completely liquefy them, grind them into powder after cooling, and obtain a molten salt electrolyte. The general formula of the molten salt electrolyte is Li 0.51 Na 0.52 K 0.18 AlCl 4.20 , melting point is about 120° C.) as the electrolyte of the battery, and a molten salt aluminum battery is assembled according to the method of Example 1;

[0055] (3) The molten salt aluminum battery obtained in step (2) is subjected to a complete discharge step, and a constant current discharge is performed at a current density of 100 mA / g to 0.2 V. The system temperature during the discharge process is 130° C., and then the completely discharged battery is disassembled, the discharged product is completely taken out, and it is soaked and washed with deionized water twice, each time for 10 minutes, and the solid product is filtered and collected. The washed solution is a LiCl solution, and the solid product is a solid Al 2 O 3 and metal oxides of Ni, Co and Mn;

[0056] (4) The solid product obtained in step (3) was placed in 20 mL of 15 wt% HCl solution, and after standing for 30 min, the product was filtered and collected. The resulting solution was NiCl2 、CoCl 2 、MnCl 2 Mixed solution, solid product is solid Al 2 O 3 .

[0057] Figure 8 The left side is the discharge curve of the molten salt aluminum battery discharge process step (3) of this embodiment, which shows that under the molten salt electrolyte, LiNi 0.8 Co 0.1 Mn 0.1 O 2 The particles can obtain 718mAh g -1 The high capacity of LiNi 0.8 Co 0.1 Mn 0.1 O 2 Completely transformed. Figure 8 The right side is the XRD diagram of the discharged product obtained in step (3) of this embodiment. According to the comparison with the standard card, the generation of Ni, Co and LiCl is confirmed (the Mn content is too low to be measured).

[0058] Example 3

[0059] A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials, comprising the following steps:

[0060] (1) Recycling waste LiNi 0.85 Co 0.1 Al 0.05 O 2 The soft pack battery is disassembled and the positive electrode material (mainly LiNi 0.85 Co 0.1 Al 0.05 O 2 ) and aluminum foil;

[0061] (2) The stripped waste positive electrode material and aluminum foil are used as positive and negative electrodes respectively, a glass fiber separator is used as a battery separator, and an alkaline molten salt electrolyte is used (the specific preparation method of the molten salt electrolyte comprises the following steps: under the protection of inert gas, AlCl 3 , NaCl, LiCl and KCl, add them into a sealed container, transfer them into an oven, keep them at 160°C for 24 hours, mix the components evenly and completely liquefy them, grind them into powder after cooling, and obtain a molten salt electrolyte. 0.44 Na 0.45 K 0.16 AlCl 4.05, melting point is about 130° C.) as the electrolyte of the battery, and a molten salt aluminum battery is assembled according to the method of Example 1;

[0062] (3) The molten salt aluminum battery obtained in step (2) is subjected to a complete discharge step, and a constant current discharge is performed at a current density of 10 mA / g to 0.25 V. The system temperature during the discharge process is 140° C., and then the completely discharged battery is disassembled, the discharged product is completely taken out, and it is soaked and washed with deionized water for 3 times, each time for 10 minutes, and the solid product is filtered and collected. The washed solution is a LiCl solution, and the solid product is a solid Al 2 O 3 and metals Ni and Co;

[0063] (4) The solid product obtained in step (3) was placed in 20 mL of 5 wt% HCl solution, and after standing for 30 min, the product was filtered and collected. The resulting solution was NiCl 2 、CoCl 2 Mixed solution, solid product is solid Al 2 O 3 .

[0064] Fig. 9 The left side is the discharge curve of the molten salt aluminum battery discharge process step (3) of this embodiment, which shows that under the molten salt electrolyte, LiNi 0.85 Co 0.1 Al 0.05 O 2 The particles can obtain 790mAh g -1 The high capacity of LiNi 0.85 Co 0.1 Al 0.05 O 2 Completely transformed. Fig. 9 The right side is the XRD diagram of the discharged product obtained in step (3) of this embodiment. According to the comparison with the standard card, the generation of Ni, Co and LiCl is confirmed.

[0065] Example 4

[0066] A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials, comprising the following steps:

[0067] (1) Recycling of waste LiCoO 2 The cylindrical battery was disassembled and the waste positive electrode material (mainly LiCoO 2 ) and aluminum foil;

[0068] (2) The stripped waste positive electrode material and aluminum foil are used as positive and negative electrodes respectively, a glass fiber separator is used as a battery separator, and an alkaline molten salt electrolyte is used (the specific preparation method of the molten salt electrolyte comprises the following steps: under the protection of inert gas, AlCl 3 , NaCl, LiCl and KCl, add them into a sealed container, transfer them into an oven, keep them at 160°C for 24 hours, mix the components evenly and completely liquefy them, and grind them into powder after cooling to obtain a molten salt electrolyte with the general formula of Li 0.55 Na 0.56 K 0.19 AlCl 4.30 , melting point is about 120° C.) as the electrolyte of the battery, and a molten salt aluminum battery is assembled according to the method of Example 1;

[0069] (3) The molten salt aluminum battery obtained in step (2) is subjected to a complete discharge step, and a constant current discharge is performed at a current density of 60 mA / g to 0.2 V. The system temperature during the discharge process is 130° C., and then the completely discharged battery is disassembled, the discharged product is completely taken out, and it is soaked and washed with deionized water twice, each time for 10 minutes, and the solid product is filtered and collected. The washed solution is a LiCl solution, and the solid product is a solid Al 2 O 3 and metal Co;

[0070] The solid product obtained in step (3) was placed in 15 mL of 12 wt% HCl solution, and after standing for 30 min, the product was filtered and collected. The resulting solution was CoCl 2 solution, the solid product is solid Al 2 O 3 .

[0071] Through XRD, TEM and hysteresis loop tests, it is proved that this method can achieve the purpose of treating waste positive electrode material LiCoO 2 Complete reconstruction of recycling.

[0072] Example 5

[0073] A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials, comprising the following steps:

[0074] (1) Recycling waste LiNi 0.6 Co 0.2 Mn 0.2 O 2 The cylindrical battery is disassembled and the waste positive electrode material (mainly LiNi 0.6 Co 0.2 Mn 0.2O 2 ) and aluminum foil;

[0075] (2) The stripped waste positive electrode material and aluminum foil are used as positive and negative electrodes respectively, a glass fiber separator is used as a battery separator, and an alkaline molten salt electrolyte is used (the specific preparation method of the molten salt electrolyte comprises the following steps: under the protection of inert gas, AlCl 3 , NaCl, LiCl and KCl, add them into a sealed container, transfer them into an oven, keep them at 160°C for 24 hours, mix the components evenly and completely liquefy them, and grind them into powder after cooling to obtain a molten salt electrolyte with the general formula of Li 0.48 Na 0.49 K 0.17 AlCl 4.15 , melting point is about 125° C.) as the electrolyte of the battery, and a molten salt aluminum battery is assembled according to the method of Example 1;

[0076] (3) The molten salt aluminum battery obtained in step (2) is subjected to a complete discharge step, and a constant current discharge is performed at a current density of 40 mA / g to 0.15 V. The system temperature during the discharge process is 130° C., and then the completely discharged battery is disassembled, and the discharged product is completely taken out and soaked and washed with deionized water for 3 times, each time for 10 minutes, and the solid product is filtered and collected. The washed solution is a LiCl solution, and the solid product is a solid Al 2 O 3 and metal oxides of Ni, Co and Mn;

[0077] The solid product obtained in step (3) was placed in 15 mL of 15 wt% HCl solution, and after standing for 30 min, the product was filtered and collected. The resulting solution was NiCl 2 、CoCl 2 、MnCl 2 Mixed solution, solid product is solid Al 2 O 3 .

[0078] Through XRD, TEM and hysteresis loop tests, it is proved that this method can be used for the waste positive electrode material LiNi 0.6 Co 0.2 Mn 0.2 O 2 Complete reconstruction of recycling.

[0079] Example 6

[0080] A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials, comprising the following steps:

[0081] (1) Recycling waste LiNi 0.5 Co 0.2 Mn 0.3 O 2 The cylindrical battery is disassembled and the waste positive electrode material (mainly LiNi 0.5 Co 0.2 Mn 0.3 O 2 ) and aluminum foil;

[0082] (2) The stripped waste positive electrode material and aluminum foil are used as positive and negative electrodes respectively, a glass fiber separator is used as a battery separator, and an alkaline molten salt electrolyte is used (the specific preparation method of the molten salt electrolyte comprises the following steps: under the protection of inert gas, AlCl 3 , NaCl, LiCl and KCl, add them into a sealed container, transfer them into an oven, keep them at 160°C for 24 hours, mix the components evenly and completely liquefy them, and grind them into powder after cooling to obtain a molten salt electrolyte with the general formula of Li 0.55 Na 0.56 K 0.19 AlCl 4.30 , melting point is about 120° C.) as the electrolyte of the battery, and a molten salt aluminum battery is assembled according to the method of Example 1;

[0083] (3) The molten salt aluminum battery obtained in step (2) is subjected to a complete discharge step, and a constant current discharge is performed at a current density of 100 mA / g to 0.1 V. The system temperature during the discharge process is 130° C., and then the completely discharged battery is disassembled, the discharged product is completely taken out, and it is soaked and cleaned once with deionized water for 10 minutes each time, and the solid product is filtered and collected. The washed solution is a LiCl solution, and the solid product is a solid Al 2 O 3 and metal oxides of Ni, Co and Mn;

[0084] (4) The solid product obtained in step (3) was placed in 30 mL of 10 wt% HCl solution, and after standing for 30 min, the product was filtered and collected. The resulting solution was NiCl 2 、CoCl 2 、MnCl 2 Mixed solution, solid product is solid Al 2 O 3 .

[0085] Through XRD, TEM and hysteresis loop tests, it is proved that this method can be used for the waste positive electrode material LiNi 0.5 Co 0.2 Mn 0.3 O2 Complete reconstruction of recycling.

Claims

1. A molten salt electrochemical driven full reconstruction recovery method for waste lithium-ion battery positive electrode materials, characterized in that: The following steps are involved: 1) Dismantling the waste lithium-ion batteries to obtain waste aluminum foil and waste positive electrode materials; 2) using the waste aluminum foil obtained in step 1) as the negative electrode and the waste positive electrode material obtained in step 1) as the positive electrode, and assembling the negative electrode, the positive electrode, an alkaline molten salt electrolyte and a separator under an inert atmosphere to obtain a molten salt aluminum battery; 3) disassembling the molten salt aluminum battery assembled in step 2) after a complete discharge step to obtain a discharge product; 4) washing the discharge product obtained in step 3) with water, filtering, collecting the filtrate to obtain a LiCl solution, and then immersing the filter residue in a dilute HCl solution for pickling, wherein the liquid after pickling is a metal chloride solution, and the solid after pickling is Al2O3, and the LiCl solution and the metal chloride solution are used to recover metal lithium salts and other metal salts and metal oxides.

2. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 1) The waste positive electrode material includes one or more of LiCoO2, ternary NCM positive electrode material, and ternary NCA positive electrode material.

3. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 2) The alkaline molten salt electrolyte has the general formula A a AlX b , wherein A is selected from at least two of Ca, Mg, Li, Na, K, Rb and Cs, X includes at least one of the halogen elements F, Cl, Br and I, 1≤a≤2, 4≤b≤5.

4. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 2) The assembly method is: the positive electrode is in contact with one side of the diaphragm, and the other side of the diaphragm is in contact with the negative electrode, a powdered alkaline molten salt electrolyte is added to the battery structure, and the battery is heated to a temperature exceeding the melting point of the alkaline molten salt electrolyte to melt the electrolyte and infiltrate the electrodes and the diaphragm, or a liquid alkaline molten salt electrolyte is injected into the battery structure and infiltrates the positive electrode, the diaphragm and the negative electrode to form the core components of the battery, and then packaged to obtain a molten salt aluminum battery.

5. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 3) Discharging step: Discharging at a constant current density of 5-100 mA / g to 0.01-0.3 V, and the system temperature during the discharge process is 80-300° C.

6. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 4) The washing step is to add deionized water and soak for 1-3 times, each time for 10 minutes.

7. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 4) The concentration of the dilute HCl solution is 5-20 wt%.

8. The molten salt electrochemical driven full reconstruction recovery method of waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: Step 4) The pickling time is 10-30 minutes.

9. A molten salt aluminum battery obtained from waste lithium-ion batteries.

10. The method for preparing a molten salt aluminum battery based on waste lithium-ion batteries according to claim 9, characterized in that: It includes the following steps: 1) Dismantling the waste lithium-ion batteries to obtain waste aluminum foil and waste positive electrode materials; 2) The waste aluminum foil obtained in step 1) is used as the negative electrode, and the waste positive electrode material obtained in step 1) is used as the positive electrode. Under an inert atmosphere, the negative electrode, the positive electrode, an alkaline molten salt electrolyte and a separator are assembled to obtain a molten salt aluminum battery.

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