Pretreatment method for battery recycling using oxidizing gas and additive, active material recovered thereby, and battery recycling method

Abstract

The present invention relates to a pretreatment method for battery recycling, wherein at least one active material selected from the group consisting of a positive electrode material and a negative electrode material is recovered from at least one workpiece selected from the group consisting of waste batteries and waste scrap, and wherein the workpiece is mixed with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture, and the mixture is heat-treated in a gaseous atmosphere containing an oxidizing gas to remove impurities other than the active material.

Description

Technology Field

[0001] The present invention relates to a technology for recovering and recycling active materials, such as positive or negative electrode materials, from waste batteries and waste scrap. More specifically, it relates to a battery recycling pretreatment method for separating active materials at low temperatures through heat treatment in an oxidizing gas atmosphere with an alkali metal compound or an alkaline earth metal compound, and removing impurities such as binders without damaging the active materials, as well as the active materials recovered thereby and the battery recycling method. Background Technology

[0003] Lithium-ion batteries have established themselves as a core energy storage device across modern industries, ranging from portable electronic devices such as smartphones and laptops to electric vehicles (EVs) and energy storage systems (ESS). In particular, as battery demand has exploded alongside the rapid growth of the EV market, the importance of waste battery recycling is increasing day by day in terms of securing a stable supply of rare metal resources—such as lithium, nickel, cobalt, and manganese, which are battery raw materials—and protecting the environment.

[0004] Battery recycling technologies can be broadly classified into urban mining and direct recycling methods. The urban mining method involves destroying the cathode material to obtain raw materials (e.g., LiOH, NiSO4, etc.). This is a technology that returns the state to ) and is subdivided into dry processes (Pyrometallurgy) and wet processes (Hydrometallurgy).

[0005] The dry process is a method of recovering metals by melting waste batteries at high temperatures (over 1000°C). It has the advantages of a simple process, flexible application, and fast processing speed, but it has disadvantages such as high energy consumption, low purity, and environmental pollution. The wet process is a method of leaching and separating metals using an acidic solution. It has the advantages of a high metal recovery rate and relatively low energy consumption, but it has disadvantages such as environmental pollution, long processing time, and high processing costs.

[0006] In contrast, the direct recycling method is a technology that restores cathode materials, such as electrodes and batteries, back into their original form using a non-destructive process. It offers the advantages of minimal environmental pollution, low cost, and the ability to directly reuse the cathode materials. To recycle waste batteries and waste scrap, they must be crushed or pulverized, and impurities other than the cathode and anode materials must be removed. While solvent-based methods exist for removing impurities, they present challenges such as complex processes and the generation of large amounts of wastewater. Another method involves high-temperature heat treatment, but this process can lead to damage to the cathode or anode materials due to the decomposition of conductive materials and fluorine-containing high-adhesion binders.

[0007] To address this, conventional methods involved adding LiOH to crushed waste batteries and waste scrap, followed by heat treatment. However, even with the addition of LiOH, high temperatures are still required to remove carbon conductive materials, and this process damages some of the cathode or anode materials. Furthermore, LiF generated during the fluorine removal process by LiOH is difficult to eliminate; this acts as another impurity, degrading the performance of the cathode or anode materials.

[0008] Meanwhile, existing processes for removing fluorine-containing binders and conductive materials mostly take place at high temperatures, leading to problems such as high energy consumption and increased environmental burden. Furthermore, these high-temperature processes during impurity removal cause equipment corrosion and shorten its lifespan, while also incurring significant costs for safety management.

[0009] Ultimately, to prevent damage to cathode or anode materials, reduce energy consumption, and improve economic efficiency, a method is needed to lower the temperature required to remove conductive materials and binders from waste batteries and waste scrap without damaging the recovered materials. The problem to be solved

[0011] One objective of the present invention is to provide a method for safely removing impurities, such as fluorine-based binders, conductive materials, and current collectors at low temperatures while efficiently recovering positive and negative electrode materials from waste batteries and waste scrap.

[0012] Another objective of the present invention is to provide a battery recycling pretreatment method that prevents performance degradation of the active material by suppressing the generation of hydrogen fluoride (HF), which is a major cause of damage to the positive and negative electrode materials.

[0013] Another objective of the present invention is to provide a method for reducing energy costs and minimizing environmental burden by efficiently removing impurities at low temperatures compared to existing high-temperature processes.

[0014] Meanwhile, other unspecified objects of the present invention will be further considered to the extent that they can be easily inferred from the following detailed description and effects. means of solving the problem

[0016] To solve the problem described above, the following solution is proposed.

[0017] A pretreatment method for battery recycling according to one embodiment of the present invention is a pretreatment method for battery recycling by recovering at least one active material selected from the group consisting of a positive electrode material and a negative electrode material from at least one workpiece selected from the group consisting of waste batteries and waste scrap, wherein the workpiece is mixed with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture, and the mixture is heat-treated in a gas atmosphere containing an oxidizing gas to remove impurities other than the active material.

[0018] In one embodiment, the oxidizing gas may be characterized as being at least one selected from the group consisting of ozone gas and chlorine gas.

[0019] In one embodiment, the alkali metal compound is at least one selected from the group consisting of NaOH and KOH, and the alkaline earth metal compound may be at least one selected from the group consisting of Ca(OH)2 and Mg(OH)2.

[0020] In one embodiment, the process of mixing the workpiece and the additive is performed through mixing so that the additive can be coated on at least a portion of the surface of the workpiece.

[0021] In one embodiment, the temperature at which the heat treatment is performed may be greater than 65°C and less than or equal to 400°C.

[0022] In one embodiment, the temperature at which the heat treatment is performed may be greater than 65 ℃ and less than 380 ℃.

[0023] In one embodiment, the temperature at which the heat treatment is performed may be 75 ℃ to 150 ℃.

[0024] In one embodiment, the impurity may include a binder containing fluorine.

[0025] In one embodiment, when the additive is NaOH or KOH, the content of the additive has an elemental ratio of Na or K to fluorine (F) in the workpiece of 0.88 or more and 2.64 or less, and when the additive is Ca(OH)2 or Mg(OH)2, the content of the additive may have an elemental ratio of Ca or Mg to fluorine (F) in the waste battery or waste scrap of 0.44 or more and 1.32 or less.

[0026] In one embodiment, the binder may be any one selected from the group consisting of Polyvinylidene Fluoride (PVDF), Polyvinyl Fluoride (PVF), Polytetrafluoroethylene (PTFE), PVDF-HFP (Polyvinylidene Fluoride-co-hexafluoropropylene), FEP (Fluorinated ethylene propylene), and Fluoroethylene Ether (FEVE).

[0027] In one embodiment, the impurity may be a conductive material.

[0028] In one embodiment, when the additive is an alkali metal compound or an alkaline earth metal compound, the current collector, which is one of the impurities, can be removed.

[0029] An active material according to another embodiment of the present invention relates to an active material recovered using a pretreatment method for battery recycling, wherein at least one active material selected from the group consisting of a positive electrode material and a negative electrode material is recovered from at least one workpiece selected from the group consisting of waste batteries and waste scrap. The method is characterized by mixing the workpiece with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture, and heat-treating the mixture in a gaseous atmosphere containing an oxidizing gas to remove impurities other than the active material.

[0030] In one embodiment, the recovered active material may include a compound formed by combining fluorine with at least one selected from the group consisting of alkali metals and alkaline earth metals.

[0031] In one embodiment, the recovered active material may not contain a compound formed by the combination of lithium and fluorine. However, the compound formed by the combination of lithium and fluorine referred to herein means a lithium and fluorine compound that is generated in excess during the heat treatment process, and does not mean that lithium and fluorine compounds generated due to natural occurrence, etc., are not included.

[0032] A battery recycling method according to another embodiment of the present invention comprises: (a) a step of recovering at least one active material selected from the group consisting of a positive electrode material and a negative electrode material from at least one workpiece selected from the group consisting of waste batteries and waste scrap, and performing a pretreatment for battery recycling; and (b) a step of heat-treating the recovered active material to restore its structure, wherein step (a) is characterized by mixing the workpiece with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture, and heat-treating the mixture in a gaseous atmosphere containing an oxidizing gas to remove impurities other than the active material. Effects of the invention

[0034] A pretreatment method for battery recycling according to one embodiment of the present invention forms a mixture by mixing at least one workpiece selected from the group consisting of waste batteries and waste scrap with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds, and heat-treats the mixture in a gas atmosphere containing an oxidizing gas to remove impurities other than the active material, thereby enabling the removal of impurities even at a temperature lower than the temperature at which a high-adhesion binder decomposes in an oxygen atmosphere.

[0035] According to the present invention, by utilizing the synergistic effect of an alkali metal compound or an alkaline earth metal compound and an oxidizing gas, a fluorine-containing binder is safely decomposed at low temperatures, and damage to the cathode and anode materials can be prevented by suppressing the generation of hydrogen fluoride through the alkali metal compound or alkaline earth metal compound and trapping it in the form of valuable metal fluoride. That is, the strong oxidizing power of the oxidizing gas promotes the decomposition of the CF and CH bonds of PVDF, and the alkali metal compound or alkaline earth metal compound immediately captures the generated hydrogen fluoride to form stable metal fluorides (e.g., NaF, KF, CaF2, MgF2). The NaF, KF, CaF2, MgF2, etc. formed in this way are economically valuable by-products that can be recovered through a subsequent washing process. Furthermore, by removing the conductive material without high-temperature heat treatment, the present invention can prevent surface damage to the cathode material or deterioration of the crystal structure caused by thermal oxidation of the conductive material, thereby effectively suppressing the degradation of the electrode active material quality.

[0036] Since the method of the present invention can be performed at significantly lower temperatures compared to conventional high-temperature processes, it is possible to drastically reduce energy consumption and solve the problems of equipment corrosion and shortened lifespan.

[0037] In particular, the active material recovered according to the method of the present invention maintains electrochemical performance similar to that of the original active material, and since a compound formed by the combination of lithium and fluorine (LiF) is not formed, the degradation of the active material's performance is prevented. Furthermore, when an alkali metal compound or an alkaline earth metal compound is used as an additive, the aluminum current collector is also removed, which has the advantage of obtaining a high-purity active material without an additional separation process.

[0038] Consequently, the present invention provides an effective pretreatment method that minimizes damage to the cathode and anode materials during the battery recycling process, reduces energy consumption, and increases economic efficiency.

[0039] Meanwhile, it should be added that even if an effect is not explicitly mentioned here, the effects described in the following specification and the provisional effects expected by the technical features of the present invention are treated as described in the specification of the present invention. Brief explanation of the drawing

[0041] FIG. 1 is a conceptual diagram showing the overall process of a pretreatment method for battery recycling according to the present invention. Figure 2 is a graph comparing charge / discharge characteristics with NaOH added (NS) and not added (S), ozone (O3) and oxygen (O2) at various temperatures, where (a) is the result at 0.1C and (b) is the result at 0.5C. Figure 3 is a graph comparing charge / discharge characteristics with and without NaOH addition, ozone and oxygen treatment at 75°C, where (a) is the result at 0.1°C and (b) is the result at 0.5°C. Figure 4 is a graph showing the cycle life characteristics according to each processing condition. Figure 5 shows the PVDF decomposition reaction through TGA analysis. (a) is a graph showing the decomposition temperature range of PVDF and NaOH, and (b) is the TGA analysis result after washing for each treatment condition. Figure 6 shows carbon black samples before and after heat treatment at 75°C in an ozone atmosphere. Figure 7 is a graph showing charge / discharge characteristics according to the reheat treatment temperature, where (a) is the result at 0.1C and (b) is the result at 0.5C. Figure 8 shows the results of comparing the charge-discharge characteristics of a sample that underwent low-temperature impurity removal treatment and washing processes using NaOH and ozone, followed by reheat treatment using ozone, with the original NCM622 (Pristine). (a) shows the charge-discharge curve at 0.1C, and (b) shows the curve at 0.5C. Figures 9(a) and (b) show changes in chemical state through XPS analysis. Figure 10 shows the results of a comparative study using KOH. (a) is the F 1s XPS analysis result, (b) is the TGA analysis result, and (c) is the charge / discharge curve of the KOH-coated_ozone_75 ℃ treated sample. Figure 11 is an image showing the effect of removing aluminum impurities through NaOH coating and ozone treatment. Figure 12 shows the thermogravimetric analysis (TGA) results of LFP scrap before treatment and an LFP sample that has undergone washing and reheat treatment after the application of NaOH and ozone technology according to the present invention. Figure 13 shows the TGA analysis results for NCM scrap before and after chlorine gas treatment. It should be noted that the attached drawings are provided as examples for reference to help understand the technical concept of the present invention, and the scope of the rights of the present invention is not limited by them. Specific details for implementing the invention

[0042] Hereinafter, with reference to the drawings, we will examine the configuration of the present invention as guided by various embodiments thereof and the effects derived therefrom. In describing the present invention, detailed descriptions of related known functions are omitted if they are deemed obvious to a person skilled in the art and could unnecessarily obscure the essence of the invention.

[0043] Recycling methods for waste batteries and waste scrap include the direct recycling of cathode and anode materials, and the method of recovering valuable metals through wet smelting after producing black powder. Direct recycling of cathode materials involves extracting undamaged cathode materials from scrap generated during the battery manufacturing process and reusing them immediately. Wet smelting using black powder involves crushing and grinding waste batteries or scrap, processing them into a form called black powder through heat treatment, and then recovering valuable metals by dissolving metal components such as lithium, nickel, and cobalt from the black powder in chemical solvents such as sulfuric acid.

[0044] Conventional recycling methods for waste batteries and waste scrap involve performing pretreatment processes including crushing, grinding, and high-temperature heat treatment to recycle the cathode and anode materials of lithium-ion batteries. That is, through pretreatment, waste batteries or waste scrap are first crushed or ground to make them small, and then the ground pieces are heat-treated at a high temperature of about 400°C or higher to burn off and remove binders (e.g., PVDF) and conductive materials (e.g., carbon black).

[0045] However, conventional pretreatment methods have several problems. First, during the crushing and grinding process, aluminum breaks into small pieces and mixes with the cathode and anode materials. Consequently, when waste batteries are crushed and ground, the risk of battery explosion increases significantly due to the incorporation of fragments during direct recycling, and the purity of the black powder is lowered during wet smelting due to metal fragments. As the purity of the black powder decreases, the cost of wet smelting inevitably increases.

[0046] In addition, if combustion is carried out at high temperatures (400–800°C) to remove fluorine-based binders and conductive materials during the heat treatment process, hydrogen fluoride (HF), water (H2O), and hydrocarbon gases (CH₄) are produced. x Gases such as ) are generated explosively, and the cathode material is damaged by these gases. Furthermore, at high temperatures, the crystal structure of the cathode material changes from a layered structure (Layered LMO) to a spinel-type structure (Spinel-type LMO), and even to a rock salt structure (Rocksalt MO). Such damage and structural deformation of the cathode material significantly reduce its electrochemical performance, particularly energy density and charge / discharge efficiency, making direct recycling difficult.

[0047] Accordingly, the present invention proposes a pretreatment method that utilizes an additive and an oxidizing gas together to remove or separate other impurities, such as binders and conductive materials, other than the anode and cathode materials, without damaging the anode or cathode materials at a low temperature of 400°C or lower. Meanwhile, the oxidizing gas used in the present invention may be at least one selected from the group consisting of ozone gas and chlorine gas. This is to verify the applicability as a powerful oxidizing agent among various oxidizing gases, and other oxidizing gases may also be similarly applied within the technical scope of the present invention.

[0048] For clarity of explanation, the following description is based on the case where the positive active material is Lithium Nickel Cobalt Manganese Oxide (NCM), but it can also be applied to other positive active materials such as Lithium Iron Phosphate (LFP), Lithium Cobalt Oxide (LCO), Lithium Manganese Oxide (LMO), Lithium Nickel Manganese Oxide (LNMO), Lithium Nickel Oxide (LNO), and Lithium Nickel Cobalt Aluminum Oxide (LNC).

[0049] FIG. 1 is a conceptual diagram showing the overall process of a pretreatment method for battery recycling according to the present invention. A pretreatment method for battery recycling according to one embodiment of the present invention is broadly composed of two steps.

[0050] First, the step involves mixing at least one workpiece selected from the group consisting of waste batteries and waste scrap with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture.

[0051] Second, the above mixture is heat-treated in a gaseous atmosphere containing an oxidizing gas to remove impurities other than the active material.

[0052] The first step of the present invention is to form a mixture by mixing at least one workpiece selected from the group consisting of waste batteries and waste scrap with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds.

[0053] The alkali metal compound or alkaline earth metal compound may be an alkali metal hydroxide or an alkaline earth metal hydroxide. More specifically, the alkali metal compound may be at least one selected from the group consisting of NaOH and KOH, and the alkaline earth metal compound may be at least one selected from the group consisting of Ca(OH)2 and Mg(OH)2. These additives can effectively trap hydrogen fluoride generated during the decomposition process of the fluorine-based binder.

[0054] The additive mixing step is performed through mixing, thereby coating the additive onto the surface of the workpiece. Specifically, by directly mixing and coating an alkali metal compound or an alkaline earth metal compound with the workpiece, an environment is created that can immediately trap hydrogen fluoride generated during the subsequent heat treatment process.

[0055] The content of the additive is determined by considering the stoichiometric ratio with respect to the fluorine (F) contained in the binder. Preferably, when the additive is NaOH or KOH, the content of the additive is preferably such that the elemental ratio of Na or K to the fluorine (F) in the workpiece is 0.88 or higher and 0.64 or lower; and when the additive is Ca(OH)2 or Mg(OH)2, the content of the additive is preferably such that the elemental ratio of Ca or Mg to the fluorine (F) in the workpiece is 0.44 or higher and 1.32 or lower. Such content ratios can effectively neutralize hydrogen fluoride generated during the decomposition process of the fluorine-based binder while preventing cost increases caused by the excessive use of additives.

[0056] The second step of the present invention is to heat-treat the mixture in a gaseous atmosphere containing an oxidizing gas to remove impurities other than the active material.

[0057] The heat treatment temperature is performed in the range of 65°C to 400°C or lower, preferably 65°C to 380°C or lower, and more preferably 75°C to 150°C. This is a significantly lower temperature compared to the high-temperature process performed at approximately 400°C or higher to remove impurities other than the existing active material.

[0058] Ozone gas or chlorine gas can be used as the oxidizing gas. Taking ozone as an example, ozone has a higher oxidizing power (about 1.6 times) than oxygen, which promotes the decomposition of CF and CH bonds in fluorine-based binders. The core principle of the present invention lies in utilizing the synergistic effect of the high oxidizing power of an oxidizing gas such as ozone and an alkali metal compound or an alkaline earth metal compound. The strong oxidizing power of the oxidizing gas promotes the decomposition of fluorine-based binders such as PVDF even at low temperatures, and through the alkali metal compound or alkaline earth metal compound, it suppresses the generation of hydrogen fluoride and traps it in the form of valuable metal fluoride, thereby forming stable metal fluorides (e.g., NaF, KF, CaF2, MgF2).

[0059] The heat treatment time is preferably at least 1 hour, no more than 24 hours, and more preferably around 6 hours. If the heat treatment time is too short, the binder removal may be incomplete, and if it is too long, energy consumption may increase and process efficiency may decrease.

[0060] The impurities removed by the pretreatment method of the present invention may be at least one selected from the group consisting of a binder, a conductive material, a separator, a current collector, and a case.

[0061] The binder removed at low temperature as an impurity by the pretreatment method of the present invention may include an anode binder and a cathode binder, and the anode binder may be at least one selected from the group consisting of Polyvinylidene Fluoride (PVDF), Polyvinyl Fluoride (PVF), Polytetrafluoroethylene (PTFE), PVDF-HFP (Polyvinylidene Fluoride-co-hexafluoropropylene), FEP (Fluorinated ethylene propylene), and Fluoroethylene Ether (FEVE), and the cathode binder may be at least one selected from the group consisting of CMC (Carboxymethyl Cellulose) and SBR (Styrene-Butadiene Rubber), PVDF-HFP (Polyvinylidene Fluoride-co-hexafluoropropylene), FEP (Fluorinated ethylene propylene), and PTFE (Polytetrafluoroethylene). In particular, the present invention has the advantage of being able to remove fluorine-containing binders, such as polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polytetrafluoroethylene (PTFE), and fluoroethylene ether (FEVE), without generating hydrogen fluoride. Above all, by preventing the formation of lithium-fluorine compounds that are difficult to remove even by washing during the binder removal process, it is possible to prevent performance degradation of the recycled active material. However, the types of binders removed by the pretreatment method of the present invention are not limited to these.

[0062] The conductive material removed at low temperature as an impurity by the pretreatment method of the present invention may be at least one of carbon black, CNT (Carbon Nanotube), graphene, and carbon fiber. However, the type of conductive material removed by the pretreatment method of the present invention is not limited thereto.

[0063] The membrane removed as an impurity at low temperature by the pretreatment method of the present invention may be a polyolefin-based membrane composed of at least one of polypropylene (PP) and polyethylene (PE), and may be a membrane with enhanced thermal stability by coating a ceramic material (e.g., alumina, silica) on the surface of the polyolefin membrane. However, the type of membrane removed by the pretreatment method of the present invention is not limited thereto.

[0064] When an alkali metal compound or an alkaline earth metal compound is used as an additive, it is possible to decompose and remove aluminum contained in waste batteries or waste scrap. That is, aluminum current collectors or aluminum impurities can be removed at low temperatures by the pretreatment method of the present invention.

[0065] Meanwhile, the pretreatment method for battery recycling according to the present invention may further include a cleaning step and a reheat treatment step after performing a step of heat treating the mixture in a gaseous atmosphere containing an oxidizing gas.

[0066] As described above, when a workpiece is mixed with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds and then heat-treated in an oxidizing gas atmosphere, fluorine contained within the polymer binder is trapped to form fluoride. By washing with water, economically valuable fluoride (e.g., NaF, KF, etc.) and by-products such as carbon materials or carbon compounds generated during the heat treatment process can be removed and recovered.

[0067] However, if the cathode material comes into contact with water during the cleaning process, performance may deteriorate due to factors such as surface structure degradation and lithium ion leakage; therefore, reheat treatment is performed to mitigate this performance degradation and stabilize the structure of the active material. During the reheat treatment process, the structure of the cathode material is restored and the surface is stabilized, thereby recovering electrochemical performance.

[0068] Reheat treatment can be performed in an oxygen atmosphere or an oxidizing gas atmosphere. When reheat treatment is performed in an oxygen atmosphere, the reheat treatment temperature may be 800°C or lower, preferably 500°C or lower, and more preferably 100 to 400°C. For example, by heat treating at around 500°C in an oxygen atmosphere, the degradation of the NCM structure can be stabilized and electrochemical performance similar to that of Pristine NCM can be secured.

[0069] When reheat treatment is performed in an oxidizing gas atmosphere, the reheat treatment temperature may be any one of 400°C or lower, greater than 65°C to 400°C or lower, preferably 75°C to 400°C, more preferably 75°C to 300°C, 75°C to 200°C, or 75°C to 100°C. In particular, it can be effectively performed at 100°C or lower, for example, at 75°C.

[0070] In particular, the reheat treatment of the pretreatment method for battery recycling according to the present invention can be performed at 400°C or lower even under an oxygen atmosphere. Considering that the temperature at which carbon materials and carbon compounds are generally removed is 400 to 500°C or higher, the reheat treatment is performed at a relatively low temperature. As the reheat treatment of the pretreatment method for battery recycling according to the present invention is performed at such a low temperature, economic efficiency can also be improved.

[0071] Furthermore, the reheat treatment of the pretreatment method for battery recycling according to the present invention can remove carbon materials and carbon compounds at a low temperature of 400°C or lower even when performed in an oxidizing gas atmosphere, and can remove carbon materials and carbon compounds at a lower temperature than in an oxygen atmosphere. The reheat treatment temperature in an oxidizing gas atmosphere can be performed at 400°C or lower, or 300°C or lower, preferably 200°C or lower, and more preferably 100°C or lower. Therefore, when the reheat treatment is performed in an oxidizing gas atmosphere, it is possible to perform it at a very low temperature of 100°C or lower, thereby increasing economic efficiency.

[0073] Example 1

[0074] NCM622 scrap (binder: PVDF, conductive material: carbon black) and NaOH (4 wt%) were mixed and coated using a mixer, and then heat-treated for 6 hours at various temperatures (65 to 400°C) in an ozone atmosphere. In the case of Example 1 and all other examples for which electrochemical evaluations were performed, unless otherwise specifically mentioned regarding the washing process and the re-heat treatment process, the washing process to recover metal fluoride, a high-value-added product that may occur after the process, and the re-heat treatment to restore the unstable structure during the washing process were applied in the same way.

[0075] Figure 2 is a graph showing the charge-discharge characteristics of samples treated with NaOH and ozone at various temperatures, where (a) is the result at 0.1C and (b) is the result at 0.5C. Table 1 below summarizes the charge-discharge characteristics of each sample at 0.1C and 0.5C in Figure 2.

[0077] [Table 1]

[0078]

[0080] Referring to Figure 2 and Table 1, the scrap (S) treated at 400°C and 700°C in oxygen (O2) and the scrap (NS) coated with NaOH as an additive treated at 65°C in ozone (O3) (NS_O3_65°C) showed inferior charge-discharge characteristics compared to the original NCM622. However, all other samples treated at temperatures above 65°C showed charge-discharge characteristics equivalent to NCM622.

[0081] In conclusion, in the pretreatment method for battery recycling according to one embodiment of the present invention, the lower limit of the heat treatment temperature in an ozone atmosphere may exceed 65°C. In addition, when heat treatment is performed in an oxygen atmosphere, the cathode material is damaged by gases such as hydrofluoric acid, but by heat treatment in an ozone atmosphere, damage caused by hydrofluoric acid gas can be prevented.

[0082] Furthermore, the pretreatment method for battery recycling according to one embodiment of the present invention has high economic efficiency as it can remove binders, conductive materials, etc. even at temperatures of 600°C or lower. To further increase economic efficiency, the heat treatment temperature may preferably be greater than 65°C and less than or equal to 400°C, and more preferably greater than 65°C and less than or equal to 380°C. Even more preferably, the lower limit of the heat treatment temperature may be 75°C or higher, and the upper limit may be 300°C or lower, 200°C or lower, 150°C or lower, or 100°C or lower.

[0084] Example 2

[0085] In this example, the heat treatment effect was compared for NCM622 scrap (binder: PVDF, conductive material: carbon black) depending on the presence or absence of an additive (NaOH) and the type of gas (ozone, oxygen). The experimental conditions involved heat treatment at 75°C for 6 hours, and four samples were prepared (S_O2: NaOH-free + oxygen, NS_O2: NaOH-free + oxygen, S_O3: NaOH-free + ozone, NS_O3: NaOH-free + ozone).

[0086] Figure 3 is a graph comparing charge-discharge characteristics with NaOH addition (NS) and no addition (S), ozone (O3) and oxygen (O2) treatment at 75°C, where (a) is the result at 0.1°C and (b) is the result at 0.5°C. Table 2 below summarizes the charge-discharge characteristics of each sample.

[0088] [Table 2]

[0089]

[0091] Referring to Figure 3 and Table 2, the combination of NaOH and ozone (NS_O3) showed the best performance (discharge capacity approximately 175.60 mAh / g, efficiency 89.70%). On the other hand, the sample treated with only ozone without NaOH (S_O3) showed a significant decrease in discharge capacity to 82.51 mAh / g and efficiency to 56.70%, while the sample treated with only oxygen without NaOH (S_O2) showed the lowest performance with a discharge capacity of 79.59 mAh / g and efficiency to 56.91%.

[0092] These results demonstrate that a synergistic effect between NaOH and ozone is essential for effective PVDF removal and active material protection at low temperatures. NaOH suppresses the generation of hydrogen fluoride during the PVDF decomposition process, while ozone promotes the decomposition of PVDF, thereby preventing damage to the cathode active material and enabling the maintenance of its original performance.

[0093] In conclusion, it was confirmed that the combination of additives and ozone in the pretreatment method for battery recycling according to the present invention yields optimal results, thereby enabling the effective removal of impurities and the maintenance of the active material's performance even at low temperatures.

[0095] Example 3

[0096] In this example, cycle life characteristics according to each treatment condition were compared. The experimental conditions were the same as in Example 2, with heat treatment at 75°C for 6 hours, and the discharge capacity retention rate of each sample over 50 cycles was measured.

[0097] Figure 4 is a graph showing the cycle life characteristics according to each treatment condition, and the results are shown in Table 3.

[0099] [Table 3]

[0100]

[0102] Referring to Figure 4 and Table 3, it can be confirmed that the NS_O3 sample maintains cycle stability similar to the original NCM622. The initial discharge capacity is approximately 160 mAh / g, and it maintains a similar capacity even after 50 cycles, demonstrating an excellent capacity retention rate.

[0103] On the other hand, the samples treated without NaOH, namely S_O3 and S_O2, not only had a low initial discharge capacity of about 57 mAh / g, but also showed a continuous decrease in capacity as the cycle progressed, dropping to about 40 mAh / g and 45 mAh / g, respectively, after 50 cycles. This is analyzed to be due to damage to the active material caused by the generation of hydrogen fluoride.

[0104] In the case of the NS_O2 sample, the initial capacity is about 140mAh / g, which is lower than that of NS_O3.

[0105] In summary, it can be confirmed once again that NaOH and O3 are crucial factors in the hydrogen fluoride neutralization reaction during low-temperature heat treatment. Ozone promotes the decomposition of PVDF, and NaOH effectively suppresses the generation of hydrogen fluoride, thereby ensuring the long-term stability of the active material.

[0106] In conclusion, it was confirmed that the combination of NaOH and ozone according to the present invention not only effectively removes PVDF even in low-temperature processes but also ensures excellent performance in terms of long-term cycle stability. This holds great significance from the perspective of actual battery recycling and reuse.

[0108] Example 4

[0109] In this example, the PVDF decomposition effect of combined NaOH and ozone treatment was analyzed through TGA (thermogravimetric analysis).

[0110] Figure 5 shows the PVDF decomposition reaction through TGA analysis. (a) is a graph showing the decomposition temperature ranges of PVDF and NaOH, where PVDF generally decomposes between 380 and 600°C and shows a rapid mass loss in this temperature range. (b) shows the TGA analysis results for NCM622 samples under different processing conditions.

[0111] In Fig. 5(b), NCM Scrap is an untreated control sample, NS_O3_75℃ is a sample treated with NaOH and ozone at 75℃, S_O2_400℃ is a sample treated with oxygen at 400℃, and S_O2_700℃ is a sample treated with oxygen at 700℃.

[0112] The most notable finding from the analysis is that the sample treated with NaOH and ozone in combination at a low temperature of 75°C (NS_O3_75°C) exhibited a TGA curve almost identical to that of the sample treated with an oxygen atmosphere at 700°C (S_O2_700°C). No mass loss due to PVDF decomposition was observed in either sample in the 380-600°C range. This implies that PVDF was completely removed through the synergistic effect of NaOH and ozone, even at a low temperature of 75°C.

[0113] On the other hand, in the untreated control group (NCM Scrap), a clear mass loss was observed in the 380-600℃ range, confirming the presence of PVDF. In the case of the sample treated in an oxygen atmosphere at 400℃ (S_O2_400℃), a mass loss due to impurities was observed.

[0114] In conclusion, TGA analysis confirmed that treatment with NaOH and ozone at a low temperature of 75°C exhibits a PVDF removal effect equivalent to treatment in a high-temperature oxygen atmosphere at 700°C. This demonstrates that the method of the present invention is an innovative technology capable of effectively removing PVDF while significantly reducing energy consumption.

[0116] Example 5

[0117] In this embodiment, the possibility of removing carbon black, a conductive material, in an ozone atmosphere was confirmed. Carbon black is a major conductive material added to provide electrical conductivity to the cathode and anode materials of lithium-ion batteries; when recovered along with the active material during battery recycling, it acts as an impurity that degrades the purity of the recycled active material.

[0118] The experiment was conducted by heat-treating carbon black samples at 75°C for 6 hours in an ozone atmosphere. Changes in the samples before and after heat treatment were observed visually and compared.

[0119] Figure 6 shows carbon black samples before and after heat treatment at 75°C in an ozone atmosphere. In the sample before heat treatment (left), black carbon black is clearly observed, whereas in the sample after heat treatment at 75°C for 6 hours in an ozone atmosphere (right), the carbon black was completely removed, showing a clean state.

[0120] This result demonstrates that the strong oxidizing power of ozone can effectively oxidize and decompose carbon-based conductive materials even at a low temperature of 75°C. Considering that the combustion of carbon materials generally takes place at high temperatures of 400 to 500°C or higher, it was confirmed that complete removal of carbon black is possible even at significantly lower temperatures in an ozone atmosphere.

[0121] The results of this embodiment demonstrate that low-temperature heat treatment in an ozone atmosphere is an effective pretreatment method capable of simultaneously removing not only the binder but also the conductive material, in addition to the binder removal effect confirmed in the preceding embodiments. This suggests that it is an economical and eco-friendly method that can effectively remove impurities while increasing the purity of the active material and reducing energy consumption in the battery recycling process.

[0123] Example 6

[0124] In this embodiment, the performance difference according to the reheat treatment temperature of NCM622 scrap treated with NaOH and ozone was evaluated.

[0125] NCM622 scrap (binder: PVDF, conductive material: carbon black) was mixed with NaOH (4 wt%) and coated, then subjected to a first heat treatment at 75°C for 6 hours in an ozone atmosphere. After the washing process, it was subjected to a re-heat treatment at various temperatures (100°C, 200°C, 400°C, 500°C) for 6 hours in an oxygen atmosphere.

[0126] Figure 7 is a graph showing charge-discharge characteristics according to the reheat treatment temperature, where (a) is the result at 0.1C and (b) is the result at 0.5C. Table 4 below summarizes the charge-discharge characteristics of each sample in Figure 7.

[0128] [Table 4]

[0129]

[0131] Looking at the charge-discharge characteristics, it can be seen that the original NCM622 (Pristine) maintains a charge-discharge profile similar to that of the original under all reheat treatment temperature conditions. Of particular note is that there is no significant difference in electrochemical performance even when the reheat treatment temperature is lowered from 500°C to 100°C.

[0132] Referring to Figure 7 and Table 4, the discharge capacity of the NS_O3_75℃_6h (reheat at O2_100℃_6h) sample at 0.1C was 171.41 mAh / g, which is 99.3% of the original NCM622 (172.58 mAh / g), while the NS_O3_75℃_6h (reheat at O2_500℃_6h) sample showed a capacity of 175.60 mAh / g, which is actually about 1.7% higher than the original NCM622. In terms of Coulombic Efficiency, it was approximately 89–90% under all reheating temperature conditions, showing a level similar to the original NCM622 (87.25%).

[0133] This result suggests that if the primary heat treatment using NaOH and ozone is sufficiently effective, the temperature of the subsequent re-heat treatment process can be lowered from the existing 500°C to 100°C, thereby significantly contributing to reduced energy consumption and process costs.

[0135] Example 7

[0136] In this embodiment, the possibility of low-temperature reheat treatment using ozone instead of oxygen was examined to further lower the temperature of the reheat treatment process and simplify the process.

[0137] NCM622 scrap (binder: PVDF, conductive material: carbon black) was mixed with NaOH (4 wt%) and coated, then subjected to a first heat treatment at 75°C for 6 hours in an ozone atmosphere. After the washing process, the material was subjected to a second heat treatment at 75°C for 6 hours in an ozone atmosphere instead of the conventional re-heat treatment at 500°C in an oxygen atmosphere.

[0138] Figure 8 shows the results of comparing the charge-discharge characteristics of a sample reheated at low temperature using ozone (NS_O3_75℃_6h(Reheat at O3_75℃_6h)) with the original NCM622 (Pristine). (a) shows the charge-discharge curve at 0.1C, and (b) shows the charge-discharge curve at 0.5C. Table 5 below summarizes the charge-discharge characteristics of each sample.

[0140] [Table 5]

[0141]

[0143] Referring to Figure 8 and Table 5, it can be seen that the sample reheated at 75°C using ozone exhibits a charge-discharge profile very similar to that of the original NCM622. The discharge capacity at 0.1C is 172.53 mAh / g for the NS_O3_75°C_6h (reheat at O3_75°C_6h) sample, which is almost the same level as the original NCM622 (172.58 mAh / g).

[0144] This result implies that by utilizing the strong oxidizing power of ozone in the reheat treatment process, residual impurities (such as carbon materials and carbon compounds) can be effectively removed even at a very low temperature of 75°C. In particular, by securing performance equivalent to Pristine NCM through ozone reheat treatment at the very low temperature of 75°C, the potential for energy savings and maximization of process efficiency was confirmed. By performing the reheat treatment process—which previously required temperatures of 400–500°C or higher in an oxygen atmosphere—at a low temperature of 75°C using ozone, the energy efficiency and economic viability of the process can be significantly improved.

[0145] In conclusion, through this embodiment, it was confirmed that not only the primary heat treatment using NaOH and ozone but also the re-heat treatment process can be performed at a low temperature (75℃). This can significantly reduce energy consumption in the entire battery recycling process and provide various advantages, such as extended equipment lifespan and improved process safety. In particular, the innovativeness of this invention is significant in that the degradation of the active material surface caused by the washing process can be effectively restored solely through low-temperature re-heat treatment at 75℃ using ozone.

[0147] Example 8

[0148] In this embodiment, changes in chemical state according to each treatment condition were investigated through XPS (X-ray Photoelectron Spectroscopy) analysis.

[0149] Figure 9 shows changes in chemical state through XPS analysis. The results of C 1s, F 1s, Li 1s, and Ni 2p spectrum analysis are presented, and the spectra of NCM Scrap, oxygen_700℃ treatment, ozone_75℃ treatment, NaOH coating treatment, NaOH coating_oxygen_75℃ treatment, and NaOH coating_ozone_75℃ treatment samples are compared.

[0150] In the C 1s spectrum, peaks corresponding to the FCF bond (approx. 291 eV) and HCH bond (approx. 286.5 eV) of PVDF are clearly observed in the untreated NCM scrap. These peaks remain in the ozone_75°C treated samples, whereas in the NaOH-coated samples (especially the NaOH-coated_ozone_75°C treated samples), these peaks disappear and only the peak corresponding to the metal carbonate (M2CO3) is observed.

[0151] In the F1s spectrum, a strong peak corresponding to the CF bond of PVDF (approx. 688 eV) appears in the NCM scrap. In the oxygen-700°C treated sample, the CF peak of PVDF is reduced, and a peak corresponding to LiF (approx. 685 eV) is observed to be generated. This indicates that hydrogen fluoride generated during the PVDF decomposition process reacted with the lithium of the active material to form LiF. On the other hand, in the NaOH-coated samples, the CF peak completely disappears, and only a peak corresponding to NaF (approx. 684.5 eV) is observed. This indicates that fluorine generated during the PVDF decomposition process reacted with NaOH to form NaF.

[0152] In the Li 1s spectrum, a peak corresponding to LiF (approx. 56 eV) is observed in the oxygen_700°C and ozone_75°C treated samples, whereas this peak is not observed in the NaOH-coated samples. Instead, peaks corresponding to lithium carbonate (Li2CO3, approx. 55.5 eV) and lithium oxide (Li2O, approx. 54.5 eV) are observed in all samples.

[0153] In the Ni 2p spectrum, a peak corresponding to nickel fluoride (NiF2, approx. 853 eV) is observed in the oxygen-700°C treated sample, whereas this peak is not observed in the NaOH-coated samples. This means that NaOH effectively suppressed the generation of hydrogen fluoride, thereby preventing the reaction with nickel.

[0154] These XPS analysis results confirm that the method of treating with NaOH and O3 together according to the present invention not only effectively removes PVDF but also prevents damage to the active material (formation of metal fluorides such as LiF and NiF2) by safely trapping fluorine in the form of NaF instead of hydrogen fluoride that may be generated.

[0155] In conclusion, XPS analysis confirmed that NaOH coating and ozone treatment safely decompose PVDF and effectively suppress hydrogen fluoride generation, thereby preserving the chemical state of the active material and preventing performance degradation.

[0157] Example 9

[0158] In this example, the effect of an alkali metal compound other than NaOH, specifically KOH, was evaluated.

[0159] Figure 10 shows the results of a comparative study using KOH. (a) is the F 1s XPS analysis result, where the CF bond of PVDF (approx. 688 eV) is observed in NCM Scrap, whereas in the KOH-coated, ozone-75°C treated sample, the CF peak disappears and a peak corresponding to KF (approx. 684.5 eV) is generated. (b) is the TGA analysis result, and since the TGA analysis result of the KOH-coated, ozone-75°C treated sample shows the same result as the NaOH-coated, ozone-75°C treated sample in Figure 5(b), it can be confirmed that residual impurities are stably removed. Figure 10(c) is the charge-discharge curve of the KOH-coated, ozone-75°C treated sample, and it can be confirmed that the KOH-coated, ozone-75°C treated sample exhibits electrochemical performance equivalent to that of the NCM622 (Pristine) sample.

[0161] [Table 6]

[0162]

[0164] Referring to Figure 10 and Table 6, the results of the charge-discharge performance analysis show that the discharge capacity of the KOH-coated, ozone-treated, 75°C sample was approximately 177.28 mAh / g, which is similar to the performance of the original NCM622 (approximately 172.58 mAh / g). The shape of the discharge curve also exhibits the characteristics of a typical NCM cathode material, which means that the simultaneous application of KOH and O3 effectively removed PVDF while maintaining the basic structure and electrochemical properties of the active material.

[0165] These results demonstrate that the method of the present invention is applicable to various alkali metal compounds in addition to NaOH, and in particular, proves that a combination of KOH and ozone can effectively remove PVDF and prevent damage to the active material. In conclusion, it was confirmed that ozone heat treatment using alkali metals safely removes the binder and conductive material of the cathode composite, making it possible to recycle the cathode material without changing its performance.

[0167] Example 10

[0168] In this embodiment, the effectiveness of treating waste anodes containing aluminum current collectors was evaluated. NCM scrap and aluminum were mixed to examine the possibility of removing the aluminum current collectors.

[0169] Figure 11 and Table 7 are images and ICP analysis results showing the effect of removing aluminum impurities through NaOH coating and ozone treatment, respectively. Image 1 is NCM scrap that does not contain aluminum, image 2 is NCM scrap containing 10 wt% aluminum, image 3 is a sample of sample 2 treated only with ozone (O3_75℃ treatment), and image 4 is a sample of sample 2 treated with NaOH and ozone (NaOH coating_O3_75℃ treatment).

[0171] [Table 7]

[0172]

[0174] As can be seen in the drawing, No. 1 general NCM scrap appears as a uniform black powder, whereas No. 2 aluminum-containing NCM scrap appears as a mixture of silver aluminum particles. Aluminum particles are still observed in No. 3 sample treated only with ozone, but in No. 4 sample treated with NaOH and ozone, all aluminum is removed, resulting in a black powder form similar to sample No. 1.

[0175] According to the ICP analysis results, the metal composition of the NCM Scrap was Ni 62.17%, Mn 17.30%, and Co 20.54%, whereas the composition of the NaOH-coated, ozone-treated 75°C sample was measured to be Ni 68.69%, Mn 18.44%, Co 12.80%, and Al 0.06%. In particular, the aluminum content is very low at the 0.06% level. In fact, the measured amount of Al is below the ICP measurement limit, which means that NaOH reacted with the aluminum and completely removed it.

[0176] While the previously examined studies on NaOH coating were limited to utilizing the cathode material by safely removing binders and conductive materials from the cathode composite, this experiment confirmed that the entire cathode (anode composite and current collector) can be treated using NaOH coating technology. In particular, it is significant that the Al foil serving as the cathode current collector can be completely decomposed, and impurities such as Al particles present within the cathode composite can be easily removed.

[0178] Example 11

[0179] In this embodiment, the effect of the pretreatment method according to the present invention on the removal of impurities from the LFP (Lithium Iron Phosphate) cathode active material was evaluated through thermogravimetric analysis (TGA).

[0180] LFP scrap (including binder and conductive material) was prepared. A portion of this LFP scrap was left untreated for comparison, and the method of the present invention was applied to the remaining portion. Specifically, the LFP scrap was coated by mixing NaOH as an additive in the same manner as the previous example of NCM scrap (NS_O3_65℃), and then heat-treated at a temperature of 75℃ for 6 hours in an environment where an ozone atmosphere was maintained.

[0181] Figure 12 shows a comparison of the thermogravimetric analysis (TGA) results of LFP scrap before treatment (LFP Scrap) and LFP samples to which NaOH and ozone technology according to the present invention has been applied (LFP Scrap (NaOH and O3 composite technology applied)).

[0182] In the case of untreated LFP scrap, mass loss began at approximately 200°C and showed a relatively large mass loss of about 6-7%, which was determined to be due to binder pyrolysis, particularly in the temperature range between approximately 300°C and 550°C. Subsequently, at temperatures above 600°C, mass loss due to conductive material pyrolysis was observed.

[0183] On the other hand, the LFP sample to which the NaOH and ozone composite technology was applied according to the method of the present invention showed only a very small mass reduction of less than about 1% relative to the initial mass during heating up to 800°C, as a result of TGA analysis. This clearly demonstrates that organic impurities such as binders and conductive materials present in the LFP scrap were very effectively removed through the low-temperature ozone treatment of the present invention.

[0184] These TGA results demonstrate that the pretreatment method of the present invention effectively removes organic impurities even from LFP cathode active materials, thereby significantly improving the purity of the active material. Therefore, the technology of the present invention can be effectively applied to the recycling of various cathode active materials, including LFP as well as NCM series, and suggests that it can contribute to the performance improvement of recycled batteries through the recovery of high-purity active materials. This confirms that the method of the present invention has broad applicability in the treatment of various types of lithium-ion battery waste.

[0186] Example 12

[0187] In this embodiment, the effectiveness of removing binders and conductive materials from NCM scrap was verified using chlorine (Cl2) gas, an oxidizing gas other than ozone. The purpose was to verify the ability of chlorine gas, an oxidizing gas with strong oxidizing power similar to ozone, to remove impurities.

[0188] The experiment was conducted by heat-treating NCM622 scrap (binder: PVDF, conductive material: carbon black) in a chlorine gas atmosphere instead of using ozone. The weight change before and after heat treatment was analyzed using TGA (thermogravimetric analysis).

[0189] Figure 13 shows the TGA analysis results for NCM scrap before and after chlorine gas treatment. NCM622 (Pristine) is a pure cathode material sample without binder and conductive material, NCM Scrap is a scrap sample containing binder and conductive material, and Cl2 gas treatment sample is a sample heat-treated in a chlorine gas atmosphere.

[0190] Analysis results showed that in the case of untreated NCM scrap, a rapid weight loss was observed in the 350-450°C range. This weight loss is caused by the decomposition of the PVDF binder and carbon black conductive material in that temperature range.

[0191] It is worth noting that the sample treated with chlorine gas showed a TGA curve almost identical to that of the pure NCM622 (Pristine) sample. No weight loss was observed in the 350-450°C range, which means that the binder and conductive material were removed by the chlorine gas.

[0192] The results of this example demonstrate that impurities in NCM scrap can be effectively removed even with chlorine gas. This is at a level similar to the effect of ozone confirmed in previous examples, proving that chlorine gas is also an oxidizing gas suitable for low-temperature pretreatment.

[0193] In conclusion, the low-temperature pretreatment method using an oxidizing gas presented in this invention is applicable not only to ozone but also to chlorine gas, which suggests that it can improve the economics and efficiency of the process by providing flexibility in the selection of oxidizing gases in the battery recycling process.

[0195] Based on the above description and embodiments, the active material recovered through the method of the present invention can be reused in the manufacture of new batteries, which can contribute to cost reduction and environmental protection through the recycling of rare metal resources. Furthermore, compared to existing high-temperature recycling processes, the method of the present invention can significantly reduce energy consumption, extend equipment lifespan, and minimize environmental burden, thereby improving the economic viability and sustainability of the battery recycling industry.

[0196] The pretreatment method for battery recycling according to the present invention is applicable to cathode materials (e.g., Lithium Iron Phosphate (LFP), Lithium Cobalt Oxide (LCO), Lithium Manganese Oxide (LMO), Lithium Nickel Manganese Oxide (LNMO), Lithium Nickel Oxide (LNO), Lithium Nickel Cobalt Aluminum Oxide (LNC), etc.) and anode materials (e.g., graphite, silicon, LTO, etc.) of lithium-ion batteries. In particular, it can be effectively applied to various types of electrodes using a fluorine-based binder such as PVDF and a conductive material.

[0197] The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it is added once again that the scope of protection of the present invention cannot be limited by obvious changes or substitutions in the technical field to which the present invention belongs.

Claims

Claim 1 A pretreatment method for battery recycling, wherein at least one active material selected from the group consisting of a positive electrode material and a negative electrode material is recovered from at least one workpiece selected from the group consisting of waste batteries and waste scrap, and the pretreatment method for battery recycling is characterized by: mixing the workpiece with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture, and heat-treating the mixture in a gas atmosphere containing an oxidizing gas to remove impurities other than the active material. Claim 2 A pretreatment method for battery recycling according to claim 1, wherein the oxidizing gas is at least one selected from the group consisting of ozone gas and chlorine gas. Claim 3 A pretreatment method for battery recycling according to claim 1, wherein the alkali metal compound is at least one selected from the group consisting of NaOH and KOH, and the alkaline earth metal compound is at least one selected from the group consisting of Ca(OH)2 and Mg(OH)2. Claim 4 A pretreatment method for battery recycling according to claim 1, wherein the process of mixing the workpiece and the additive is performed through mixing, and the additive is coated on at least a portion of the surface of the workpiece. Claim 5 A pretreatment method for battery recycling according to claim 1, characterized in that the temperature at which the heat treatment is performed is greater than 65 ℃ and less than or equal to 400 ℃. Claim 6 A pretreatment method for battery recycling according to claim 1, characterized in that the temperature at which the heat treatment is performed is greater than 65 ℃ and less than 380 ℃. Claim 7 A pretreatment method for battery recycling according to claim 1, characterized in that the temperature at which the heat treatment is performed is 75 to 150 ℃. Claim 8 A pretreatment method for battery recycling according to claim 1, characterized in that the impurity comprises at least one selected from the group consisting of a fluorine-containing binder, a conductive material, and an aluminum current collector. Claim 9 A pretreatment method for battery recycling according to claim 8, wherein, when the additive is NaOH or KOH, the content of the additive has an elemental ratio of Na or K to fluorine (F) in the workpiece of 0.88 or more and 2.64 or less, and when the additive is Ca(OH)2 or Mg(OH)2, the content of the additive has an elemental ratio of Ca or Mg to fluorine (F) in the waste battery or waste scrap of 0.44 or more and 1.32 or less. Claim 10 A pretreatment method for battery recycling according to claim 8, wherein the binder is selected from the group consisting of Polyvinylidene Fluoride (PVDF), Polyvinyl Fluoride (PVF), Polytetrafluoroethylene (PTFE), PVDF-HFP (Polyvinylidene Fluoride-co-hexafluoropropylene), FEP (Fluorinated ethylene propylene), and Fluoroethylene Ether (FEVE). Claim 11 The present invention relates to an active material recovered using a pretreatment method for battery recycling, wherein the active material is recovered from at least one workpiece selected from the group consisting of waste batteries and waste scrap, and at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds is mixed with the workpiece to form a mixture, and the mixture is heat-treated in a gas atmosphere containing an oxidizing gas to remove impurities other than the active material. Claim 12 An active material according to claim 11, characterized in that the recovered active material comprises a compound formed by combining fluorine with at least one selected from the group consisting of alkali metals and alkaline earth metals. Claim 13 An active material according to claim 11, characterized in that the recovered active material does not contain a compound formed by the combination of lithium and fluorine. Claim 14 (a) a step of recovering at least one active material selected from the group consisting of a positive electrode material and a negative electrode material from at least one workpiece selected from the group consisting of waste batteries and waste scrap, and performing a pretreatment for battery recycling; and (b) a step of heat-treating the recovered active material to restore its structure; wherein step (a) is characterized by mixing the workpiece with at least one additive selected from the group consisting of alkali metal compounds and alkaline earth metal compounds to form a mixture, and heat-treating the mixture in a gas atmosphere containing an oxidizing gas to remove impurities other than the active material.

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