Regenerated lithium ion battery and method for repairing, regenerating and recycling waste lithium ion battery

Abstract

The invention belongs to the technical field of waste battery treatment, and provides a regenerated lithium ion battery and a method for repairing, regenerating and recycling a waste lithium ion battery. According to the method, the layered structure of the lithium cobalt oxide material is repaired by adopting a chemical or physical method, so that the original crystal structure and electrochemical performance of the lithium cobalt oxide material are recovered, and the stability of the lithium cobalt oxide material is improved. After the structure is repaired, the repaired lithium cobalt oxide material is uniformly mixed with a magnesium source and a titanium source, and magnesium-titanium double doping is carried out through technologies such as high-temperature solid-phase reaction or hydrothermal synthesis. The process can effectively improve the conductivity and the ion migration ability of the material, so that the cycle performance and the energy density of the material are remarkably improved. The doped material has higher specific capacity, cycling stability and more excellent charge and discharge efficiency. The technology provided by the invention not only provides an innovative scheme for recycling and reusing the waste lithium cobalt oxide battery, but also can effectively reduce the environmental pollution and promote the sustainable development of the lithium ion battery material.

Description

Technical Field

[0001] This invention relates to the field of waste battery treatment technology, specifically to a regenerated lithium-ion battery and a method for repairing, regenerating, and recycling waste lithium-ion batteries. Background Technology

[0002] With the growing global demand for renewable energy and electric vehicles, the use of lithium-ion batteries is becoming increasingly widespread. Lithium cobalt oxide (LiCoO2) batteries, widely used in portable electronics, electric vehicles, and energy storage systems, hold a significant market position due to their excellent electrochemical properties. However, as these batteries reach the end of their lifespan, the effective recycling and reuse of the rare resources within lithium cobalt oxide batteries has become a critical issue that urgently needs to be addressed.

[0003] Lithium cobalt oxide batteries primarily consist of metallic elements such as lithium, cobalt, and nickel, which have significant economic value. However, with advancements in battery technology and market expansion, a large number of used batteries have emerged, resulting not only in resource waste but also potential environmental pollution. Therefore, effective used battery recycling technologies urgently need to be developed to achieve resource recycling and reduce environmental risks.

[0004] The electrochemical performance of lithium cobalt oxide batteries is primarily influenced by their crystal structure, with the layered structure enabling efficient insertion and extraction of lithium ions during charge and discharge. After multiple charge-discharge cycles, this layered structure can be damaged, leading to capacity degradation and decreased cycle stability. Therefore, repairing the layered structure is a crucial step in improving the performance of spent lithium cobalt oxide batteries, effectively extending their lifespan and reducing waste generation.

[0005] Recent studies have found that introducing magnesium into lithium cobalt oxide materials can significantly improve their electrochemical performance. Magnesium doping not only enhances the structural stability of the material but also strengthens the conductivity of lithium ions, thereby improving the battery's specific capacity and cycle performance. The mechanism of magnesium doping mainly lies in its optimization of the lithium-ion migration path in the electrode material, reducing structural changes that occur during battery charging and discharging.

[0006] Although some research has been conducted on the recycling and reuse of spent lithium-ion batteries, many challenges remain. For example, traditional recycling methods often require complex chemical treatments, resulting in high costs and energy consumption. Furthermore, research on layered structure repair and magnesium-titanium dual doping is relatively limited, and a systematic technological framework has not yet been established. Therefore, exploring more efficient and environmentally friendly recycling technologies to achieve the efficient reuse of lithium cobalt oxide batteries is a current research focus.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] This invention is made to solve the above-mentioned problems, and aims to provide a method for repairing and regenerating waste lithium-ion batteries, and a magnesium doping technology for the layered structure repair of waste lithium cobalt oxide batteries.

[0009] In a first aspect, the present invention provides a method for repairing, regenerating and recycling waste lithium-ion batteries, characterized by the following steps: Step S1, solvothermal synthesis: S-LCO and oxalic acid are mixed and ground evenly according to a predetermined mass ratio, deionized water is added, and then placed in a hydrothermal reactor, sodium persulfate and sodium hydroxide are added, and the reaction is carried out at 80℃~150℃ for 2~12 hours to obtain the reacted lithium cobalt oxide material, so as to optimize the material performance; Step S2: Cool the reacted lithium cobalt oxide material and crush it to a specific particle size to ensure the uniformity of subsequent doping; Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:1 to 1:10, and grind for 1-2 hours; Step S4: Mix the magnesium source and titanium source with the pulverized lithium cobalt oxide material at a mass ratio of 1:1 to 1:10, and grind for 3 to 6 hours to ensure that the magnesium and titanium elements are evenly distributed in the lithium cobalt oxide material. Step S5: Grind the ground mixture and lithium carbonate at a mass ratio of 1:1. After thorough grinding, transfer the mixture to a ceramic boat and calcine to obtain the calcined product. Step S6: After the reaction is complete, the calcined product is cooled to room temperature, excess magnesium and titanium sources are washed off, separated and dried to obtain magnesium-titanium doped lithium cobalt oxide material.

[0010] The waste lithium-ion battery repair, regeneration and recycling method provided by the present invention may also have the following feature: wherein, in step S2, the specific particle size is 1μm~10μm.

[0011] The waste lithium-ion battery repair, regeneration and recycling method provided by the present invention may also have the following features: in step S3, the magnesium source is magnesium sulfate or magnesium chloride, and the titanium source is titanium dioxide; when it is magnesium chloride, the mass ratio of the mixed magnesium chloride and titanium dioxide to the pulverized lithium cobalt oxide material is 1:5.

[0012] The waste lithium-ion battery repair, regeneration and recycling method provided by the present invention may also have the following feature: in step S1, the grinding method is manual grinding or ball milling.

[0013] The waste lithium-ion battery repair, regeneration and recycling method provided by the present invention may also have the following feature: in step S5, the ground mixture is calcined using a heated solid-phase reaction method or a hydrothermal synthesis method.

[0014] The waste lithium-ion battery repair, regeneration and recycling method provided by the present invention may also have the following feature: wherein the grinding mixture is calcined using a heated solid-phase reaction method, specifically: the mixture is placed in a high-temperature furnace and heated at a temperature of 400℃~900℃ for 6~12 hours.

[0015] The waste lithium-ion battery repair and recycling method provided by this invention may also have the following features: the specific operation of step S1 is as follows: 1g of S-LCO and oxalic acid are mixed and ground evenly in a mass ratio of 5:1, and then deionized water is added at a liquid-to-solid ratio of 200mL / g. The mixture is stirred at room temperature and pressure for 20 minutes to obtain lithium cobalt oxide material treated with oxalic acid. The lithium cobalt oxide material treated with oxalic acid is then placed in a hydrothermal reactor, and 26g of sodium persulfate and 0.4g of sodium hydroxide are added. The mixture is reacted at 80℃~150℃ for 2~12 hours to obtain the reacted lithium cobalt oxide material, thereby optimizing the material performance.

[0016] The waste lithium-ion battery repair, regeneration, and recycling method provided by this invention may also have the following feature: In step S6, after the reaction is completed, the material is cooled to room temperature, and excess magnesium and titanium sources are washed with deionized water, separated using a centrifuge, and dried. The amount of excess magnesium and titanium sources is obtained by measuring the Mg and Ti content using inductively coupled plasma (ICP) assay.

[0017] The waste lithium-ion battery repair, regeneration, and recycling method provided by this invention may also include a pretreatment step for lithium cobalt oxide materials: The pretreatment step for lithium cobalt oxide materials specifically comprises: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material, and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution; Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven; Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with dilute acid to remove surface oxides in order to improve the accessibility and reactivity of the material. Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet obtained in step S0-3 in a 5% NaOH solution with a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then, wash the positive electrode active material with 2 L of deionized water and dry it at 60 °C for 12 h to obtain S-LCO.

[0018] The waste lithium-ion battery repair, regeneration and recycling method provided by the present invention may also have the following feature: wherein the dilute acid is dilute hydrochloric acid or dilute sulfuric acid with a concentration of 1mol / L-3mol / L.

[0019] The present invention also provides a regenerated lithium-ion battery, wherein the cathode material is a magnesium-titanium doped lithium cobalt oxide material prepared by the aforementioned waste lithium-ion battery repair and regeneration recycling method.

[0020] The role and effect of invention This invention relates to a method for repairing, regenerating, and recycling spent lithium-ion batteries, specifically a method involving magnesium (Mg) and titanium (Ti) doping after repairing the layered structure. This method employs chemical or physical methods to repair the layered structure of lithium cobalt oxide material, aiming to restore its original crystal structure and electrochemical performance, and improve its stability. After structural repair, the repaired lithium cobalt oxide material is uniformly mixed with a magnesium source (e.g., magnesium chloride, magnesium sulfate, etc.) and a titanium source, and then subjected to magnesium-titanium co-doping through high-temperature solid-state reaction or hydrothermal synthesis techniques. This process effectively improves the material's conductivity and ion migration ability, thereby significantly enhancing its cycle performance and energy density.

[0021] For the doped materials, this invention verifies their superior performance through electrochemical testing, including higher specific capacity, cycle stability, and better charge-discharge efficiency. Simultaneously, scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to analyze the microstructure and composition of the materials to confirm the effectiveness of the magnesium-titanium dual doping and the integrity of the layered structure.

[0022] The technology provided by this invention not only offers an innovative solution for the recycling and reuse of waste lithium cobalt oxide batteries, but also effectively reduces environmental pollution and promotes the sustainable development of lithium-ion battery materials.

[0023] This study transforms the surface phase change layer into a layered structure that enhances material stability through reconstruction modification. By using a small amount of metal surface doping, the electrochemical performance degradation that may result from direct metal doping is avoided. Simultaneously, the stability of the recycled material is enhanced, improving Li+ intercalation during relithiation while maintaining the integrity of the overall crystal structure, thus improving its cycle performance. Furthermore, doping with Mg and Ti imparts higher surface stability and stronger mechanical strength to the material. This approach addresses the core pain points of traditional recycling technologies, such as incomplete structural repair (e.g., spinel phase residue, cation disorder), high energy consumption (pyrometallurgical processes require temperatures above 1200℃), and heavy pollution (wet processes produce 8 tons / ton of cobalt-containing wastewater), and achieves the desired Mg... 2+With selective occupancy of Li⁺ sites (site occupancy energy is 0.32 eV lower than that of Co sites) and directional repair of layered structures, the waste lithium-ion battery repair and recycling method and the recycled lithium-ion battery of the present invention have multiple core advantages, including thorough structural repair, superior electrochemical performance, economic and environmental benefits, and forward-looking industry applications.

[0024] The recycling and reuse of spent lithium cobalt oxide batteries not only reduces the environmental burden but also achieves resource recycling. Repairing the layered structure of lithium cobalt oxide batteries and effectively doping them with magnesium and titanium will help restore their electrochemical performance, thereby promoting the sustainable development of battery materials. In the future, with continuous technological advancements and increasing market demand, this research field will demonstrate even broader application prospects and potential value. Attached Figure Description

[0025] Figure 1 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images from an embodiment of the present invention; Figure 2 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images from two embodiments of the present invention; Figure 3 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images from three embodiments of the present invention; Figure 4 These are X-ray photoelectron spectroscopy (XPS) images from three embodiments of the present invention; Figure 5 These are electrochemical performance images from three embodiments of the present invention; Figure 6 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images from four embodiments of the present invention; Figure 7 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images from five embodiments of the present invention; Figure 8 These are scanning electron microscope (SEM) images and transmission electron microscope (TEM) images from six embodiments of the present invention. Detailed Implementation

[0026] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following describes in detail a regenerated lithium-ion battery and a method for repairing, regenerating and recycling waste lithium-ion batteries, in conjunction with embodiments and accompanying drawings.

[0027] Unless otherwise specified, the raw materials and reagents used in the following examples can be purchased from conventional commercial channels.

[0028] The method for repairing, regenerating, and recycling spent lithium-ion batteries provided by this invention, wherein lithium cobalt oxide material is obtained in step S0, includes the following specific steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte according to conventional methods in the field to prevent environmental pollution.

[0029] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven. The specific operation of this step is as follows: The disassembled positive electrode material was immediately rinsed with deionized water and then dried in an oven at 80°C until a constant weight was achieved, indicating the removal of electrolyte. The positive electrode material was sheet-like with a multi-layered structure, containing positive electrode active material, carbon black, PVDF, and aluminum foil. Next, the positive electrode material was cut into square sheets ranging from 5×5mm to 50×50mm for subsequent experiments.

[0030] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid to remove surface oxides, improve the material's accessibility and reactivity, and obtain the treated lithium cobalt oxide material. The specific operation is as follows: The positive electrode material of the battery is immersed in a diluted 1 mol / L to 3 mol / L acidic solution (such as dilute hydrochloric acid or dilute sulfuric acid) to chemically remove lithium cobalt oxide adhering to the aluminum foil. After immersion, it is thoroughly rinsed with deionized water to remove any residual acid and dissolved substances. The separated lithium cobalt oxide material and aluminum foil are dried separately for subsequent processing. The separated lithium cobalt oxide material is referred to as the processed lithium cobalt oxide material.

[0031] Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet obtained in step S0-3 in a 5% (w / w) NaOH solution with a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then wash the positive electrode active material with 2 L of water and dry it at 60 °C for 12 h to obtain S-LCO.

[0032] <Implementation 1> A method for repairing, regenerating, and recycling spent lithium-ion batteries specifically includes the following steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution.

[0033] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven.

[0034] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid at a solid-liquid ratio of 1:10 to remove surface oxides, improve the accessibility and reactivity of the material, and obtain the treated lithium cobalt oxide material.

[0035] Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet in a 5% (w / w) NaOH solution at a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then wash the positive electrode active material with 2 L of water and dry it at 60 °C for 12 h to obtain S-LCO.

[0036] Step S1: Repair the layered structure of the treated lithium cobalt oxide material using a solvothermal synthesis method: Grind 1g of S-LCO and oxalic acid at a mass ratio of 5:1, mix them evenly, add deionized water, the liquid-to-solid ratio is 200mL / g, stir at room temperature and pressure for 20min, put the lithium cobalt oxide material treated with oxalic acid into a hydrothermal reactor, add 26g of sodium persulfate and 0.4g of sodium hydroxide, the reaction temperature is 80℃, the pressure is about 0.047 MPa, and the reaction time is 6 hours to optimize the material properties.

[0037] Step S2, Cooling and Pulverizing: After the hydrothermal reaction, the material is cooled naturally in the air and then pulverized to a size of 1μm~10μm using a grinder to ensure the uniformity of subsequent doping.

[0038] Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:3 and grind for 1-2 hours.

[0039] Step S4, Mixing: Select magnesium chloride (MgCl2). According to the doping ratio, the mixture of magnesium chloride and titanium dioxide is mixed with the hydrothermally heated lithium cobalt oxide material at a ratio of 1:5 to achieve the best doping effect. Mix the pulverized lithium cobalt oxide with the magnesium and titanium sources evenly, and process it using a ball mill for 3-6 hours to ensure that the magnesium element is evenly distributed in the lithium cobalt oxide material.

[0040] Step S5, reaction: Choose the heating solid-phase reaction method: Heated solid-state reaction method: The mixture and lithium carbonate are ground at a mass ratio of 1:1. After thorough grinding, the mixture is transferred to a ceramic boat and placed in a high-temperature furnace. It is heated at 900°C for 8 hours to obtain the calcined product.

[0041] Step S6, Cooling and Washing: After the reaction is complete, wait for the material (calcined product) to cool to room temperature, wash the excess magnesium and titanium sources with deionized water, separate them using a centrifuge and dry them.

[0042] from Figure 1(a) The scanning electron microscope (SEM) image shows that cracks or depressions still exist on the surface of the recycled material particles, and the pre-doped layer is not completely covered; some particles have fragmented deposits on their edges. The overall integrity of the particles is acceptable, but the surface smoothness is poor.

[0043] Figure 1 (b) The transmission electron microscope (TEM) image shows that the overall lattice fringes of the regenerated material are blurred and locally broken, and the layered structure features of the R-3m space group cannot be clearly identified; the Fourier transform (FFT) diffraction spots are irregularly distributed, there are diffuse spots of impurity phase (spinel phase), the interface between the predoped layer and the matrix is ​​blurred, and there are no obvious single crystal features.

[0044] <Example 2> A method for repairing, regenerating, and recycling spent lithium-ion batteries specifically includes the following steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution.

[0045] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven.

[0046] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid at a solid-liquid ratio of 1:10 to remove surface oxides and improve the accessibility and reactivity of the material.

[0047] Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet in a 5% (w / w) NaOH solution at a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then wash the positive electrode active material with 2 L of water and dry it at 60 °C for 12 h to obtain S-LCO.

[0048] Step S1: Repair the layered structure of the treated lithium cobalt oxide material using a solvothermal synthesis method: Grind 1g of S-LCO and oxalic acid at a mass ratio of 5:1, mix them evenly, add deionized water, the liquid-to-solid ratio is 200mL / g, stir at room temperature and pressure for 20min, put the lithium cobalt oxide material treated with oxalic acid into a hydrothermal reactor, add 26g of sodium persulfate and 0.4g of sodium hydroxide, the reaction temperature is 100℃, and the time is 6 hours to optimize the material performance.

[0049] Step S2, Cooling and Grinding: After the hydrothermal reaction, the material is cooled naturally in the air and then ground to a size of 10 μm using a grinder to ensure the uniformity of subsequent doping.

[0050] Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:3 and grind for 1-2 hours.

[0051] Step S4, Mixing: Select magnesium chloride (MgCl2). According to the doping ratio, the mixture of magnesium chloride and titanium dioxide is mixed with the hydrothermally heated lithium cobalt oxide material at a ratio of 1:5 to achieve the best doping effect. Mix the pulverized lithium cobalt oxide with the magnesium and titanium sources evenly, and process it using a ball mill for 3-6 hours to ensure that the magnesium element is evenly distributed in the lithium cobalt oxide material.

[0052] Step S5, reaction: Choose the heating solid-phase reaction method: Heated solid-phase reaction method: Grind the mixture and lithium carbonate at a mass ratio of 1:1. After thorough grinding, transfer the mixture to a ceramic boat and place it in a high-temperature furnace. Heat at 900°C for 8 hours.

[0053] Step S6, Cooling and Washing: After the reaction is complete, wait for the material to cool to room temperature, wash the excess magnesium source with deionized water, separate it using a centrifuge and dry it.

[0054] from Figure 2 As shown in the scanning electron microscope (SEM) image of (a), the overall particles of the recycled material cover the surface in a continuous thin film shape with reduced thickness fluctuations and no "island" gaps; there is no rough phase change layer residue on the surface, only extremely thin uniform protrusions in some areas, indicating good density.

[0055] Figure 2 (b) The transmission electron microscope (TEM) image shows that the overall lattice fringes of the recycled material are continuous and clear, and the (003) crystal plane fringes of LiCoO2 can be identified.

[0056] <Implementation 3> A method for repairing, regenerating, and recycling spent lithium-ion batteries specifically includes the following steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution.

[0057] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven.

[0058] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid at a solid-liquid ratio of 1:10 to remove surface oxides and improve the accessibility and reactivity of the material.

[0059] Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet in a 5% (w / w) NaOH solution at a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then wash the positive electrode active material with 2 L of water and dry it at 60 °C for 12 h to obtain S-LCO.

[0060] Step S1: Repair the layered structure of the treated lithium cobalt oxide material using a solvothermal synthesis method: Grind 1g of S-LCO and oxalic acid at a mass ratio of 5:1, mix them evenly, add deionized water, the liquid-to-solid ratio is 200mL / g, stir for 20min at room temperature and pressure, put the lithium cobalt oxide material treated with oxalic acid into a hydrothermal reactor, add 26g of sodium persulfate and 0.4g of sodium hydroxide, the reaction temperature is 120℃, and the time is 6 hours to optimize the material performance.

[0061] Step S2, Cooling and Grinding: After the hydrothermal reaction, the material is cooled naturally in the air and then ground to a size of 10 μm using a grinder to ensure the uniformity of subsequent doping.

[0062] Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:3 and grind for 1-2 hours.

[0063] Step S4, Mixing: Select magnesium chloride (MgCl2). According to the doping ratio, the mixture of magnesium chloride and titanium dioxide is mixed with the hydrothermally heated lithium cobalt oxide material at a ratio of 1:5 to achieve the best doping effect. Mix the pulverized lithium cobalt oxide with the magnesium and titanium sources evenly, and process it using a ball mill for 3-6 hours to ensure that the magnesium element is evenly distributed in the lithium cobalt oxide material.

[0064] Step S5, reaction: Choose the heating solid-phase reaction method: Heated solid-phase reaction method: Grind the mixture and lithium carbonate at a mass ratio of 1:1. After thorough grinding, transfer the mixture to a ceramic boat and place it in a high-temperature furnace. Heat at 900°C for 8 hours.

[0065] Step S6, Cooling and Washing: After the reaction is complete, wait for the material to cool to room temperature, wash the excess magnesium source with deionized water, separate it using a centrifuge and dry it.

[0066] from Figure 3The low-magnification scanning electron microscope (SEM) images (ai) show that the overall surface of the recycled material particles is smooth, without obvious penetrating microcracks or large-area defect areas. This phenomenon directly indicates that the macroscopic damage on the material surface is significantly repaired after the surface doping reconstruction process. Compared with the cycle-induced cracks commonly found on the surface of waste lithium cobalt oxide (S-LCO), the pre-doped layer formed by Mg-Ti doping in the recycled material can uniformly cover the particle surface, avoiding the problem of local defect aggregation that is prone to occur in traditional repair processes. At the same time, it can be clearly observed at low magnification that the overall shape of the recycled material particles (such as spherical or polygonal) is not significantly different from the original particle size, and no particle breakage or agglomeration occurs due to the repair process. This provides a guarantee for the particle dispersion and mechanical strength during the subsequent preparation of battery electrodes, and can effectively prevent particle focusing due to particle shape. Figure 3 The high-magnification SEM images (a-ii) further reveal the microscopic details of the recycled material surface: the surface exhibits no localized protrusions, depressions, or fragmented deposits, only a uniform and dense morphology, which is directly related to the uniform deposition characteristics of the pre-doped layer. In contrast to the rough, heterogeneous phase transition layer on the surface of waste materials caused by the formation of spinel phases (such as LiCo2O4), the pre-doped layer w of the recycled material forms a continuous and uniformly thick surface barrier. This not only reduces direct contact between the electrolyte and the material surface, lowering interfacial side reactions, but also constructs a smoother lithium-ion transport channel. The uniform surface structure avoids the "bottleneck effect" in the lithium-ion transport process, making it easier for lithium ions to migrate from the electrolyte to the active sites inside the material, laying the microstructural foundation for subsequent conversion into high-quality cathode materials. Morphological distortion can lead to a decrease in electrode compaction density or structural collapse during charge and discharge.

[0067] Figure 3 The low-magnification transmission electron microscope (TEM) images (bi) reveal the overall crystal structure distribution of the recycled material: there are no obvious disordered regions or heterogeneous phases (such as spinel or rock salt phases) within the material, and the overall crystal lattice arrangement exhibits continuous and regular characteristics. Analysis of the lattice orientation in different regions of the image shows that the recycled material has a high degree of crystal orientation consistency, without local lattice distortion or orientation disorder caused by the recycling of waste materials—this phenomenon originates from Mg. 2+ and Ti 4+ Directed diffusion during high-temperature reconstruction: Mg 2+ Priority occupation of Li + The lattice framework is supported by ionic pillars, inhibiting the migration of Co atoms into the Li layer and thus preventing the formation of disordered phases. A MgTiO3 nanocrystalline protective layer forms on the surface of the OR-LCMO material regenerated by Mg-TiO2 co-doping. The structural integrity observed under low-magnification TEM provides macroscopic crystal structure support for subsequent high-magnification observation and performance verification. Figure 3In the high-resolution transmission electron microscope (HRTEM) images (b-ii), the lattice fringes of the recycled material clearly exhibit clear and continuous single-crystal characteristics: the lattice fringes are free of breaks, dislocations, or blurred areas, and the fringe spacing is uniform and conforms to the layered structure parameters of LiCoO2. Fourier transform (FFT) analysis of this region revealed a regular hexagonal symmetrical distribution of diffraction spots, which perfectly matches the typical FFT characteristics of layered structures in the R-3m space group, directly confirming that the layered structure of the recycled material has been completely repaired. Compared to the fringe breaks or polycrystalline diffraction characteristics caused by lattice collapse in waste materials, the recycled material, through Mg-Ti surface dual doping, not only restores the integrity of the layered structure but also improves the single crystallinity of the crystal. This structural optimization significantly reduces the lattice resistance during lithium-ion insertion / extraction, providing a crystal structure-level guarantee for the material's excellent electrochemical performance (such as high capacity and long-term cycling stability).

[0068] from Figure 4 (a) It can be observed that after doping and reconstruction of the surface phase transition layer and subsequent lithiation, the intensities of the peaks corresponding to CO and OC=O are significantly reduced. From Figure 4 (b) shows a significant increase in peak intensity and area at 529.58 eV; Figure 4 In (c), the fitted XPS spectrum shows only one set of peaks, indicating that the Co on the surface of the recycled material has been completely converted to Co after relithiation. 3+ The peak at 780.1 eV in the Co 2p spectrum corresponds to a typical diamagnetic Co peak. 3+ Oxides, consistent with the characteristics of LiCoO2 materials; in Figure 4 In (d), the XPS peak shift amplitude is positively correlated with the crystallinity of the MgTiO3 protective layer—when Ti 2p exhibits a main peak at 455.4 eV (corresponding to Ti 4+ In the coordination environment of MgTiO3, its strong electronegativity is transferred to the neighboring Co site through the oxygen atom, synergistically with Mg 2+ The lattice doping effect, together with the lattice doping effect, induces a significant reduction in the Co 2p binding energy.

[0069] like Figure 5(a) Compared to the other three lithium cobalt oxide materials, the recycled material exhibits a smaller semicircle, indicating a significant reduction in charge transfer impedance at the electrode / electrolyte interface. This phenomenon suggests that the recycled material has a faster charge transfer capability during charge and discharge, enhancing the material's reaction kinetics. Thanks to the effective repair of the layered structure of the recycled material, its resistance also decreases, further indicating that the material possesses superior electronic conductivity and kinetic performance. This structural repair may be related to the stability of the crystal structure after Mg-Ti dual doping, making the lithium-ion insertion and extraction process smoother, thereby reducing energy loss in the electrochemical reaction.

[0070] Figure 5 (b) The rate performance of different materials is shown within a voltage window of 3–4.6 V. The recycled material exhibits excellent reversible discharge capacity, with a peak capacity of 0.02 A g under different rate conditions. -1 170.4 mAh / g, 0.1 A g -1 162.4 mAh / g, 0.2 A g -1 145.7 mAh / g, 0.4 A g -1 127.4 mAh / g, 0.6 A g -1 At 107.7 mAh / g, and even at 1 A g -1 It can still maintain a good performance of 58.6 mAh / g.

[0071] like Figure 5 As shown in (c), the test results indicate that the recycled material maintains a reversible discharge capacity of 160.2 mAh / g after 100 cycles, with a capacity retention rate of 97.28%. The high specific capacity of the recycled material is mainly due to the effective reconstruction of the surface spinel structure during its relithiation process, which is almost identical to that of C-LCO. In addition, Mg doping increases the interlayer spacing, thereby optimizing the Li⁺ replenishment effect and further improving the specific capacity of the material. Furthermore, Mg-Ti dual doping provides a more stable lattice structure for the material surface, enhances the corrosion resistance of the doped layer, and reduces electrolyte loss during cycling.

[0072] like Figure 5 (d) shows that the recycled material exhibits high redox peaks, indicating its rapid charge transfer kinetics, which complements its excellent electrochemical performance. This efficient charge transfer capability is likely closely related to the material's structural characteristics and the optimization effect of Mg-Ti dual doping. Furthermore, the peaks near 3.8V and 4.4V reflect reversible phase transition behavior, suggesting that the material structure can be effectively stabilized during charge and discharge, thus supporting lithium-ion insertion and extraction.

[0073] like Figure 5 As shown in (e), the charge-discharge specific capacity of the recycled material is more stable after 100 cycles. This further verifies the advantages of recycled materials in terms of high-rate and long-cycle performance.

[0074] <Implementation 4> A method for repairing, regenerating, and recycling spent lithium-ion batteries specifically includes the following steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution.

[0075] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven.

[0076] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid at a solid-liquid ratio of 1:10 to remove surface oxides and improve the accessibility and reactivity of the material.

[0077] Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet in a 5% (w / w) NaOH solution at a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then wash the positive electrode active material with 2 L of water and dry it at 60 °C for 12 h to obtain S-LCO.

[0078] Step S1: Repair the layered structure of the treated lithium cobalt oxide material using a solvothermal synthesis method: Grind 1g of S-LCO and oxalic acid at a mass ratio of 5:1, mix them evenly, add deionized water, the liquid-to-solid ratio is 200mL / g, stir at room temperature and pressure for 20min, put the lithium cobalt oxide material treated with oxalic acid into a hydrothermal reactor, add 26g of sodium persulfate and 0.4g of sodium hydroxide, the reaction temperature is 140℃, and the time is 6 hours to optimize the material performance.

[0079] Step S2, Cooling and Grinding: After the hydrothermal reaction, the material is cooled naturally in the air and then ground to a size of 10 μm using a grinder to ensure the uniformity of subsequent doping.

[0080] Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:3 and grind for 1-2 hours.

[0081] Step S4, Mixing: Select magnesium chloride (MgCl2). According to the doping ratio, the mixture of magnesium chloride and titanium dioxide is mixed with the hydrothermally heated lithium cobalt oxide material at a ratio of 1:5 to achieve the best doping effect. Mix the pulverized lithium cobalt oxide with the magnesium and titanium sources evenly, and process it using a ball mill for 3-6 hours to ensure that the magnesium element is evenly distributed in the lithium cobalt oxide material.

[0082] Step S5, reaction: Choose the heating solid-phase reaction method: Heated solid-phase reaction method: Grind the mixture and lithium carbonate at a mass ratio of 1:1. After thorough grinding, transfer the mixture to a ceramic boat and place it in a high-temperature furnace. Heat at 900°C for 8 hours.

[0083] Step S6, Cooling and Washing: After the reaction is complete, wait for the material to cool to room temperature, wash the excess magnesium source with deionized water, separate it using a centrifuge and dry it.

[0084] from Figure 6 (a) The scanning electron microscope (SEM) image shows that the recycled material has local cracks, wrinkles or stacking; a small number of agglomerated particles form on the surface, resulting in an uneven surface, which destroys the density and makes it impossible to form a continuous barrier.

[0085] Figure 6 (b) The transmission electron microscope (TEM) image shows that the edges of the lattice stripes of the regenerated material are blurred, and there is local "dislocation". The spacing of the (003) crystal plane stripes fluctuates; the interface between the predoped layer and the substrate is blurred, and there are no obvious single crystal characteristics.

[0086] <Implementation 5> A method for repairing, regenerating, and recycling spent lithium-ion batteries specifically includes the following steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution.

[0087] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven.

[0088] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid at a solid-liquid ratio of 1:10 to remove surface oxides and improve the accessibility and reactivity of the material.

[0089] Step S1: Repair the layered structure of lithium cobalt oxide material using a solvothermal synthesis method: Grind 1g of S-LCO and oxalic acid at a mass ratio of 5:1, mix them evenly, add deionized water, the liquid-to-solid ratio is 200mL / g, stir at room temperature and pressure for 20min, put the lithium cobalt oxide material treated with oxalic acid into a hydrothermal reactor, add 26g of sodium persulfate and 0.4g of sodium hydroxide, the reaction temperature is 120°C, and the time is 4 hours to optimize the material performance.

[0090] Step S2, Cooling and Grinding: After the hydrothermal reaction, the material is cooled naturally in the air and then ground to a size of 10 μm using a grinder to ensure the uniformity of subsequent doping.

[0091] Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:3 and grind for 1-2 hours.

[0092] Step S4, Mixing: Select magnesium chloride (MgCl2). According to the doping ratio, the mixture of magnesium chloride and titanium dioxide is mixed with the hydrothermally heated lithium cobalt oxide material at a ratio of 1:5 to achieve the best doping effect. Mix the pulverized lithium cobalt oxide and magnesium source evenly, and process with a ball mill for 3-6 hours to ensure that the magnesium element is evenly distributed in the lithium cobalt oxide material.

[0093] Step S5, reaction: Choose the heating solid-phase reaction method: Heating solid-phase reaction method: Place the mixture in a high-temperature furnace and heat it at 900°C for 8 hours.

[0094] Step S6, Cooling and Washing: After the reaction is complete, wait for the material to cool to room temperature, wash the excess magnesium source with deionized water, separate it using a centrifuge and dry it.

[0095] from Figure 7 (a) The scanning electron microscope (SEM) image shows that the particle surface is basically free of cracks, but there are a few “point-like” uncovered areas (no pre-doped layer); the particle shape is intact and there is no agglomeration, but the surface smoothness is slightly lower than that under 6h conditions.

[0096] Figure 7 (b) The transmission electron microscope (TEM) image shows clear lattice fringes of the regenerated material, but the fringes are slightly blurred in the edge regions.

[0097] <Implementation 6> A method for repairing, regenerating, and recycling spent lithium-ion batteries specifically includes the following steps: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material (lithium cobalt oxide), and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution.

[0098] Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven.

[0099] Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with 2 mol / L dilute hydrochloric acid at a solid-liquid ratio of 1:10 to remove surface oxides and improve the accessibility and reactivity of the material.

[0100] Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet in a 5% (w / w) NaOH solution at a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then wash the positive electrode active material with 2 L of water and dry it at 60 °C for 12 h to obtain S-LCO.

[0101] Step S1: Repair the layered structure of the treated lithium cobalt oxide material using a solvothermal synthesis method: Grind 1g of S-LCO and oxalic acid at a mass ratio of 5:1, mix them evenly, add deionized water, the liquid-to-solid ratio is 200mL / g, stir at room temperature and pressure for 20min, put the lithium cobalt oxide material treated with oxalic acid into a hydrothermal reactor, add 26g of sodium persulfate and 0.4g of sodium hydroxide, the reaction temperature is 120℃, and the time is 8 hours to optimize the material performance.

[0102] Step S2, Cooling and Grinding: After the hydrothermal reaction, the material is cooled naturally in the air and then ground to a size of 10 μm using a grinder to ensure the uniformity of subsequent doping.

[0103] Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:3 and grind for 1-2 hours.

[0104] Step S4, Mixing: Select magnesium chloride (MgCl2). According to the doping ratio, the mixture of magnesium chloride and titanium dioxide is mixed with the hydrothermally heated lithium cobalt oxide material at a ratio of 1:5 to achieve the best doping effect. Mix the pulverized lithium cobalt oxide with the magnesium and titanium sources evenly, and process it using a ball mill for 3-6 hours to ensure that the magnesium element is evenly distributed in the lithium cobalt oxide material.

[0105] Step S5, reaction: Choose the heating solid-phase reaction method: Heated solid-phase reaction method: Grind the mixture and lithium carbonate at a mass ratio of 1:1. After thorough grinding, transfer the mixture to a ceramic boat and place it in a high-temperature furnace. Heat at 900°C for 8 hours.

[0106] Step S6, Cooling and Washing: After the reaction is complete, wait for the material to cool to room temperature, wash the excess magnesium source with deionized water, separate it using a centrifuge and dry it.

[0107] from Figure 8 (a) The scanning electron microscope (SEM) image shows that the local stacking of recycled materials forms a “multilayer structure”; the particle surface is smooth and crack-free, but the density is reduced (overgrowth leads to interlayer voids) and a uniform barrier cannot be formed.

[0108] Figure 8 (b) The transmission electron microscope (TEM) image shows that the center of the lattice fringes of the regenerated material is clear, but the edge areas are blurred due to the excessive thickness of the pre-doped layer.

[0109] The role and effect of the embodiments The above embodiments relate to a method for repairing, regenerating, and recycling waste lithium-ion batteries, specifically a method involving magnesium (Mg)-titanium (Ti) dual doping after repairing the battery's layered structure. With the increasing prevalence of electric vehicles and portable electronic devices, the use of lithium-ion batteries is gradually increasing, leading to the generation of a large number of waste lithium cobalt oxide batteries. Effectively recycling and reusing the materials in these batteries, especially improving their electrochemical performance, has significant economic and environmental implications.

[0110] This method first involves recycling and pre-processing spent lithium cobalt oxide batteries to remove the outer casing and impurities, ensuring the extraction of usable lithium cobalt oxide material. Next, chemical or physical methods are used to repair the layered structure of the lithium cobalt oxide material, aiming to restore its original crystal structure and electrochemical performance, and improve its stability.

[0111] After structural repair, the repaired lithium cobalt oxide material is uniformly mixed with a magnesium source (such as magnesium chloride or magnesium sulfate), and magnesium doping is performed through high-temperature solid-state reaction or hydrothermal synthesis. This process effectively improves the material's conductivity and ion migration ability, thereby significantly enhancing its cycle performance and energy density.

[0112] For the doped material, its superior performance was verified through electrochemical testing, including higher specific capacity, cycle stability, and better charge-discharge efficiency. Simultaneously, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the microstructure and composition of the material to confirm the effectiveness of magnesium doping and the integrity of the layered structure.

[0113] The technology provided in the above embodiments not only offers an innovative solution for the recycling and reuse of waste lithium cobalt oxide batteries, but also effectively reduces environmental pollution and promotes the sustainable development of lithium-ion battery materials.

[0114] This study uses Mg 2+The synergistic design of surface doping and a MgTiO3 nanocrystalline protective layer constructs a multi-dimensional regulatory system in lithium cobalt oxide cathode materials, encompassing "bulk lattice stabilization, interfacial chemical functionalization, and high-voltage tolerance optimization." This provides a new strategy for addressing the cycle degradation and interfacial failure issues of layered cathode materials: at the bulk structure regulation level, Mg... 2+ Ions effectively suppress Li by substituting Li sites (XRD shows a rightward shift of the 003 crystal plane diffraction peak and shrinkage of the c-axis of the crystal lattice). + / Co 3+ The mixed arrangement of cations significantly delays the irreversible transformation of the α-NaFeO2 layered structure into a disordered rock salt phase. Therefore, the waste lithium-ion battery repair and recycling method and the recycled lithium-ion battery of this invention have multiple core advantages, including thorough structural repair, superior electrochemical performance, economic and environmental benefits, and forward-looking industry applications.

[0115] The recycling and reuse of spent lithium cobalt oxide batteries not only reduces the environmental burden but also achieves resource recycling. Repairing the layered structure of lithium cobalt oxide batteries and effectively doping them with magnesium will help restore their electrochemical performance, thereby promoting the sustainable development of battery materials. In the future, with continuous technological advancements and increasing market demand, this research field will demonstrate even broader application prospects and potential value.

[0116] The obtained recycled material (magnesium-doped lithium cobalt oxide) exhibits a reversible discharge capacity of 170.2 mAh / g at 0.1C and maintains a high rate performance of 57.6 mAh / g at 5C within a voltage window of 3-4.6V. After 100 cycles, the reversible discharge capacity is 159.2 mAh / g, with a capacity retention rate of 97.6%. It possesses a high redox peak (fast charge transfer kinetics) and stable charge-discharge specific capacity after cycling, and its overall electrochemical performance is close to that of commercial lithium cobalt oxide (C-LCO).

[0117] In addition, the surface of the recycled material is smooth and free of obvious microcracks. Compared with the surface defects of waste lithium cobalt oxide (S-LCO), the surface smoothness is significantly improved after repair. Furthermore, SEM images show that the shape and size of the material particles have not changed significantly, which can avoid the reduction in mechanical strength and the degradation of electrochemical performance caused by particle morphology distortion.

[0118] Furthermore, the lattice fringes of the recycled material exhibit clear single-crystal characteristics. Fourier transform (FFT) verification shows that the layered structure of its R-3m space group has been completely restored. There are no obvious disordered lattice or spinel phase characteristics, providing a complete crystal channel for the efficient insertion and extraction of lithium ions.

[0119] The recycled material, after fitting, showed only one set of characteristic peaks, indicating that the surface Co element had been completely converted into Co. 3+The peak at 780.1 eV corresponds to a typical diamagnetic Co. 3+ The oxide has the same Co valence state characteristics as pure phase LiCoO2, ensuring the consistency of the material's electrochemical performance.

[0120] Compared to other lithium cobalt oxide materials (such as S-LCO and direct regenerated material R-LCO), the regenerated material has a significantly smaller charge transfer impedance at the electrode / electrolyte interface (corresponding to the semicircle diameter in the Nyquist plot), indicating that the regenerated material has a faster charge transfer capability and better reaction kinetics performance during charge and discharge.

[0121] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for repairing, regenerating, and recycling waste lithium-ion batteries, characterized in that, Includes the following steps: Step S1, Solvent thermal synthesis: S-LCO and oxalic acid are mixed and ground evenly according to a predetermined mass ratio, then deionized water is added, and then the mixture is placed in a hydrothermal reactor. Sodium persulfate and sodium hydroxide are added, and the mixture is reacted at 80℃~150℃ for 2~12 hours to obtain the reacted lithium cobalt oxide material, so as to optimize the material performance. Step S2: Cool the reacted lithium cobalt oxide material and crush it to a specific particle size to ensure the uniformity of subsequent doping; Step S3: Mix the magnesium source and titanium source evenly at a mass ratio of 1:1 to 1:10, and grind for 1-2 hours; Step S4: Mix the magnesium source and titanium source with the pulverized lithium cobalt oxide material at a mass ratio of 1:1 to 1:10, and grind for 3 to 6 hours to ensure that the magnesium and titanium elements are evenly distributed in the lithium cobalt oxide material. Step S5: Grind the ground mixture and lithium carbonate at a mass ratio of 1:

1. After thorough grinding, transfer the mixture to a ceramic boat and calcine to obtain the calcined product. Step S6: After the reaction is complete, the calcined product is cooled to room temperature, excess magnesium and titanium sources are washed off, separated and dried to obtain magnesium-titanium doped lithium cobalt oxide material.

2. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that: in, In step S2, the specific particle size is 1μm~10μm.

3. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that: in, In step S3, the magnesium source is magnesium sulfate or magnesium chloride, and the titanium source is titanium dioxide; when magnesium chloride is used, the mass ratio of the mixture of magnesium chloride and titanium dioxide to the pulverized lithium cobalt oxide material is 1:

5.

4. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that: in, In step S1, the grinding method is manual grinding or ball milling.

5. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that: in, In step S5, the ground mixture is calcined using a heated solid-phase reaction method, specifically by placing the mixture in a high-temperature furnace and heating it at 400℃~900℃ for 6~12 hours.

6. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that: in, In step S6, after the reaction is complete, the material is cooled to room temperature, and excess magnesium and titanium sources are washed with deionized water, separated and dried using a centrifuge.

7. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that: in, The specific operation of step S1 is as follows: 1g of S-LCO and oxalic acid are mixed and ground evenly in a mass ratio of 5:

1. Deionized water is added at a liquid-to-solid ratio of 200mL / g. The mixture is stirred at room temperature and pressure for 20 minutes to obtain lithium cobalt oxide material treated with oxalic acid. The lithium cobalt oxide material treated with oxalic acid is then placed in a hydrothermal reactor, and 26g of sodium persulfate and 0.4g of sodium hydroxide are added. The mixture is reacted at 80℃~150℃ for 2~12 hours to obtain the reacted lithium cobalt oxide material, so as to optimize the material performance.

8. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 1, characterized in that, It also includes a pretreatment step for lithium cobalt oxide materials: The specific pretreatment steps for lithium cobalt oxide materials are as follows: Step S0-1, Dismantling of used batteries: Use special tools to dismantle used lithium cobalt oxide batteries, remove the positive electrode material, and properly dispose of the negative electrode material and electrolyte to prevent environmental pollution; Step S0-2, Lithium cobalt oxide material separation: Separate the cathode material, clean off surface impurities and contaminants, wash with deionized water, and dry to constant weight in a vacuum oven; Step S0-3, Pretreatment: Collect the lithium cobalt oxide material obtained in step S0-2, and acid wash it with dilute acid to remove surface oxides in order to improve the accessibility and reactivity of the material. Step S0-4, dissolving aluminum foil: Soak the positive electrode sheet obtained in step S0-3 in a 5% NaOH solution with a liquid-to-solid ratio of 60 mL / g to remove the aluminum foil. Then, wash the positive electrode active material with 2 L of deionized water and dry it at 60 °C for 12 h to obtain S-LCO.

9. The method for repairing, regenerating, and recycling waste lithium-ion batteries according to claim 8, characterized in that: in, The dilute acid is dilute hydrochloric acid or dilute sulfuric acid with a concentration of 1 mol / L to 3 mol / L.

10. A regenerated lithium-ion battery, characterized in that, Its positive electrode material is a magnesium-titanium doped lithium cobalt oxide material prepared by the waste lithium-ion battery repair, regeneration and recycling method according to any one of claims 1-9.

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