Method for ion reconstruction regeneration of positive electrode material in waste battery and application thereof

Abstract

This invention belongs to the field of lithium battery material regeneration technology, specifically relating to a method and application of ion reconstruction regeneration of cathode materials in waste batteries. A gas bubbling method is used to uniformly disperse waste cathode black powder in a suspension of a regenerator precursor source composed of composite anions, achieving coverage of the regenerator precursor on the surface of the black powder particles and penetration into the internal voids of the particles. Further calcination treatment is then performed to achieve ion reconstruction of the cathode material in the waste battery using the regenerator. This invention's regeneration process utilizes the deep penetration and ion reconstruction effect of the regenerator ions to achieve full restoration of the layered structure and form a fast ion conductor layer on the particle surface and grain boundaries, significantly improving the ion mobility at the solid-solid interface. This significantly enhances the specific capacity, cycle life, and rate performance of all-solid-state, polymer gel, and liquid lithium battery systems with high requirements for interface transport, providing a new approach for the high-quality, high-value recycling and upgrading of waste cathode materials.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery material regeneration technology, specifically relating to an ion reconstruction and regeneration method for cathode materials (layered oxide cathode materials in lithium-ion batteries) in waste batteries and its application. Background Technology

[0002] With the large-scale application of lithium-ion batteries, the number of retired lithium-ion batteries has surged. The lithium, nickel, cobalt, and manganese metals contained in their cathodes possess both resource value and environmental risks. Traditional recycling processes mainly extract high-value metals through pyrometallurgy and hydrometallurgy. Pyrometallurgy separates metals through high-temperature smelting, but lithium recovery rates are low, and metal alloying is severe, with the recycling process accompanied by high energy consumption and toxic gas emissions. Hydrometallurgy uses acid leaching, which improves metal recovery rates, but the purification of the leaching solution is complex and generates large amounts of acidic and alkaline wastewater, which is detrimental to environmental protection. Therefore, developing cathode ion reconstruction and regeneration technology that combines low energy consumption, high metal recovery rates, preservation of structural characteristics, and green environmental protection is crucial for resource recycling and the upgrading of the energy storage industry.

[0003] Patent document 1 (application number: 202411872549.X) discloses a method for direct recycling of ternary cathode materials. This method involves prolonged, high-speed mixing of eutectic lithium salt with waste single-crystal ternary cathode powder, allowing the former to replenish the latter with lithium. The recycled ternary cathode material is then obtained through a preparation process including sintering, sieving, mixing with metal oxides, secondary sintering, and secondary sieving. This method effectively reduces the loss of high-value metal materials in traditional metallurgy and effectively improves the rate performance and discharge capacity of liquid lithium batteries.

[0004] Patent document 2 (application number: 202210251888.0) discloses a method for directly recycling failed lithium cobalt oxide cathode material. The method involves reacting lithium source and dopants with failed lithium cobalt oxide at high temperature for a long time. While replenishing the lithium source of lithium cobalt oxide, the dopants occupy the internal vacancies, thereby repairing and strengthening the structure of the resulting recycled lithium cobalt oxide cathode material, thereby improving the capacity of the material under high voltage.

[0005] Existing direct regeneration technologies still have significant limitations. While the aforementioned high-temperature, long-duration sintering process can partially repair lithium loss and structural defects in waste layered cathode materials, it neglects the problem of heterogeneous phases (such as rock salt phases) generated in large quantities within the waste layered oxides, resulting in incomplete repair of the layered structure. Furthermore, existing direct regeneration methods are primarily suited for single-crystal cathodes. For the more prevalent polycrystalline cathode waste, there is no effective solution to the contact failure problem caused by internal grain boundaries and cracks. Typically, an additional "crush-reshape" process is required to transform it into a single-crystal structure to eliminate defects. This not only increases energy consumption and process complexity but also sacrifices the material's high metal recovery rate and the advantage of preserving its bulk structure. Therefore, the electrochemical performance of the regenerated product is usually inferior to that of the original cathode, and its application value still has considerable room for improvement. Summary of the Invention

[0006] The main objective of this invention is to address the shortcomings of existing technologies by proposing a method and application for ion reconstruction and regeneration of cathode materials (layered oxide cathode materials in lithium-ion batteries) in waste batteries.

[0007] To achieve the above objectives, the present invention can be implemented through the following technical solutions: A method for ion reconstruction and regeneration of cathode materials in waste batteries involves using a gas bubbling method to uniformly disperse waste cathode black powder in a regenerator precursor suspension, thereby achieving the coverage of the regenerator precursor on the surface of the black powder particles and its penetration into the pores inside the particles; followed by further calcination treatment to achieve ion reconstruction of the cathode materials in waste batteries using the regenerator.

[0008] The regenerant precursor suspension is obtained by simultaneously adding powders containing lithium, phosphorus, and zirconium sources to a preheated organic solvent and mixing them thoroughly. The molar ratio of lithium, phosphorus, and zirconium in the precursor suspension is 1.5-3:1.5-3:1, and the ratio between the components can be any arrangement within the given numerical range, such as 1.5:1.5:1, 1.5:1.6:1, 1.6:1.7:1, etc., within the allowable range.

[0009] The amount of lithium source added is 0.3 to 1 wt% of the mass of waste layered cathode black powder; the mass percentage can be any value and range within the specified range, such as 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.

[0010] The liquid-solid mass ratio of the regenerator precursor suspension to the waste positive electrode black powder is 5:1-20:1. The mass ratio can be any value and range within the selected ratio range, such as 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, etc.

[0011] The phosphorus-containing lithium source powder can be obtained directly from one or more of lithium dihydrogen phosphate, lithium phosphate, lithium hexafluorophosphate and their derivatives, or it can be prepared by reacting zirconium phosphate with one or more lithium salt substances, wherein the lithium salt substances are lithium hydroxide, lithium carbonate and lithium oxide. The zirconium source powder is derived from one or more of zirconium nitrate hydrate, zirconium oxynitrate hydrate, zirconium oxychloride hydrate, and zirconium oxysulfate hydrate; the organic solvent is one or more of anhydrous ethanol, methanol, propanol, n-propanol, isopropanol, ethylene glycol, and glycerol.

[0012] The regenerant precursor suspension contains an elemental source composed of complex anions (i.e., lithium, phosphorus, and zirconium), and its composition may be Li x A 3-x B y (PO4) z (0 < x <2, 0≤y≤1, 2≤ z The elemental composition of the compound is as follows: A is zirconium, a three-dimensional framework forming element; B is a dopant element of the doped lithium phosphorus zirconium oxide derivative, including one or more atoms such as sodium, potassium, aluminum, gallium, scandium, magnesium, calcium, and zinc that can be doped for lithium sites; one or more dopant atoms such as calcium, aluminum, iron, gallium, manganese, vanadium, chromium, niobium, tantalum, molybdenum, tungsten, tin, titanium, and lanthanum that can be doped for zirconium sites; one or more atoms such as arsenic, vanadium, silicon, and germanium that can be doped for phosphorus sites; and one or more atoms such as fluorine, nitrogen, and sulfur that can be doped for oxygen sites.

[0013] Furthermore, the suspension can be prepared using known material preparation methods such as sol-gel method, hydrothermal synthesis method, and coprecipitation method, with the sol-gel method being the preferred preparation method.

[0014] To elaborate further, S1. Heat the organic solvent to temperature T1, and then simultaneously add phosphorus-containing lithium source and zirconium source powder to the organic solvent, and stir until it reaches a suspension state to obtain the regenerator precursor; Furthermore, a certain amount of organic solvent is added to the reactor, the organic solvent is heated to temperature T1, and then phosphorus-containing lithium source and zirconium source powder are added simultaneously from both ends of the reactor and stirred until a suspension is obtained to obtain the regenerator precursor. S2. Heat the regenerator precursor suspension to temperature T2, then introduce a stabilizing gas under continuous stirring, and add waste positive electrode black powder to fully disperse and evenly obtain a mixed solution. Stir for 12 hours under temperature T2 and continuous introduction of stabilizing gas to achieve the coverage of the regenerator precursor on the surface of the black powder particles and the penetration into the pores inside the particles. S3. After the above reaction, stop the introduction of stabilizing gas, evaporate the mixture obtained in S2 at temperature T3, and further dry to remove liquid residue to obtain a mixed powder of waste positive electrode and regenerator precursor. S4. The mixed powder obtained above is calcined at high temperature to achieve regenerant penetration and in-situ structural regeneration of waste cathode particles. After cooling, it is sieved to obtain the in-situ repaired and regenerated layered cathode material.

[0015] The regeneration is an in-situ repair, which includes three steps: First, the composite anion constituent element source (including lithium, phosphorus and zirconium sources) penetrates into the grain boundaries and interfaces of the cathode particles; then, under high temperature, the regeneration units and target groups in the element source are oriented into the crystal lattice on the surface of the grain to achieve structural regeneration; finally, the remaining composite anion constituent elements form conductive units and are transformed into a fast ion conductor coating with a certain amount of coating on the particle surface and in the internal gaps.

[0016] The fast ion conductor coating has a coverage amount of 0.8wt%-12wt%. A preferred coverage amount is 1.5wt%.

[0017] The stable gas is one or more of oxygen, nitrogen, and air.

[0018] The temperature range of T1 is 30-55℃ (the temperature range can be any value or range within a proportional range, such as 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55℃, etc.), and the temperature range of T2 is 40-85℃ (the temperature range can be any value or range within a proportional range, such as 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 5...). 9, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85℃, etc.), the temperature range of T3 is 70-100℃ (the temperature range can be any value and range between the proportional ranges, for example, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100℃, etc.); The drying temperature range in S3 is 60-90℃ (the temperature range can be any value or range between proportional ranges, such as 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90℃, etc.), the drying time is 5-12 hours, and the drying atmosphere is air and / or oxygen.

[0019] In the S4 high-temperature calcination, the heating rate is 1-10℃ / min (the heating rate range can be any value or range within the proportional range, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10℃ / min, etc.) to 650-850℃ (the temperature range can be any value or range within the range, such as 650, 660, 670℃, etc.), the holding time is 0.5-6h (the time range can be any value or range within the range, such as 0.5, 0.6, 0.7, 0.8, 0.9, etc.), and the sintering atmosphere is oxygen.

[0020] The waste cathode black powder is waste layered cathode black powder extracted from all-solid, polymer gel, and liquid lithium batteries.

[0021] The waste cathode black powder contains one or more transition metal oxide cathode materials with a layered structure. The transition metal oxide cathode materials are selected from lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium-rich manganese-based oxides (LiNiO2). x Li2MnO3·(1- x )LiMO3 (M=Ni,Co,Mn, etc., 0.1≤ x ≤0.5), lithium nickel cobalt manganese oxide ternary materials (LiNi) 1-x- y Co x Mn y O2, 0≤ x ≤0.3, 0≤ y ≤0.5) and lithium nickel cobalt aluminum oxide (LiNi x Co y Al 1-x-y O2, 0.8≤ x ≤0.95, 0.02≤ y Any one or more combinations of ≤0.2).

[0022] The surface and grain boundaries of the layered cathode material powder that has been obtained through in-situ repair and regeneration are coated with a lithium phosphorus zirconium oxygen fast ion conductor layer.

[0023] The fast ion conductor coating has a coverage amount of 0.8wt%-12wt% (the mass percentage can be any value and range within the selected proportion range, for example, 0.8%, 0.9%, 1%, ... etc.). The preferred coverage amount is 1.5wt%.

[0024] An application of the method, wherein the positive electrode material obtained from ion-reconstructed recycled waste batteries is used as a polymer gel lithium battery or a liquid lithium battery.

[0025] A regenerated lithium battery, wherein the positive electrode of the battery contains the positive electrode material from the waste battery regenerated by the ion reconstruction method described above.

[0026] The regenerated lithium batteries include solid-state batteries, polymer gel lithium batteries, and liquid batteries.

[0027] The negative electrode active material of the solid-state battery includes commonly used materials such as elemental lithium, elemental indium, elemental silicon, elemental chromium, elemental tin, lithium-containing transition metal nitrides, graphite, lithium alloys, and silicon-carbon composites. A preferred negative electrode active material is a lithium alloy.

[0028] The solid electrolyte of the solid-state battery includes commonly used materials, such as sulfide electrolytes (e.g., binary compounds such as Li2S-GeS2, Li2S-P2S5, and Li2S-SiS2, and ternary compounds such as Li2S-MeS2-P2S5 (Me=Si, Ge, Sn, Al, etc.)), oxide electrolytes (e.g., perovskite-structured lithium lanthanum titanium oxide, garnet-structured lithium lanthanum zirconium oxide, fast ion conductors (LISICON, NASICON type)), polymer electrolytes (e.g., polyethylene oxide, polypropylene oxide, polyether, polyacrylonitrile, polymethyl methacrylate, polyethylene oxide, polyvinylidene fluoride), and halides (e.g., Li a MX4 type, Li a (MX6 type, dihalogenated). The preferred solid electrolyte is sulfide Li6PS5Cl or a composite material with a polymer.

[0029] The negative electrode active material of the polymer gel battery includes commonly used materials such as elemental lithium, lithium alloys, graphite, silicon-carbon, and quinone-based polymers. Preferred negative electrode active materials are lithium or lithium alloys.

[0030] The electrolyte of the polymer gel battery includes commonly used materials such as polyethylene oxide gel electrolyte, polyvinylidene fluoride gel electrolyte, polyacrylonitrile-based gel electrolyte, and polymer-inorganic composite gel electrolyte. A preferred electrolyte is a polyethylene oxide gel electrolyte.

[0031] The negative electrode active material of the liquid battery includes commonly used materials such as lithium metal, graphite, and SiO2. x CVD silicon-carbon and hard carbon are options. Silicon-carbon is the preferred anode active material.

[0032] The electrolyte of the liquid battery comprises commonly used materials and consists of lithium salts (e.g., lithium hexafluorophosphate, lithium bisfluorosulfonyl imide) and solvents (e.g., cyclic carbonates, chain carbonates, fluoroethylene carbonates).

[0033] The principle of this invention is as follows: The high-valence zirconium ions in the regenerator lithium phosphorus zirconium oxide can target and replace low-valence transition metal sites such as nickel, cobalt, and manganese in heterogeneous phases (such as rock salt phases). This high-valence cation doping induces transition metal vacancies and disturbs the local lattice coordination environment, opening channels for the regenerated lithium ions to enter the crystal lattice. The residual lithium phosphorus zirconium oxide component in the regenerator acts as a conductive element, forming a fast-ion conductor layer on the material surface and at grain boundaries. Furthermore, Zr... 4+ The high bond energy Zr-O bond formed with oxygen can enhance the structural stability of the layered framework, inhibit phase transitions during material recycling, and ensure the recycling stability of recycled materials.

[0034] The above-mentioned invention effect is achieved through the following key technologies: (1) Liquid-solid mixing stage of regenerator precursor and waste layered cathode black powder: There are a large number of nano-level channels (such as grain boundaries, cracks, etc.) inside the failed polycrystalline cathode black powder. Under the combined action of rotor stirring and stabilizing gas bubbling, the regenerator precursor and the failed cathode black powder are fully mixed, which promotes the precursor to fully wrap the black powder particles and penetrate into the particles through nano-level channels. (2) Drying stage of mixed liquid: By controlling the drying conditions, the regenerator precursor distributed on the surface and / or gaps of the black powder is kept uniform and stable, and is tightly bonded to the attached crystal grains. (3) The mixed powder will go through two stages during the calcination process: Calcination stage I (350-500℃): The regenerator precursor melts and completes deep penetration into the particles, while lithium phosphorus zirconium oxygen regenerator is generated in situ on the surface of the crystal grains; Calcination stage II (500℃-target temperature): Zr in the regenerator 4+ By targeting and locating heterogeneous phase regions, the closed nickel layer in the rock salt phase is opened, creating lithium intercalation space. This drives the anti-occupied nickel and lithium ions to their respective positions and their directional transformation into a layered structure. It also promotes the entry of regenerated elementary lithium ions into the crystal lattice, ultimately completing the material structure regeneration. Simultaneously, the residual regenerator lithium phosphorus zirconium oxide forms a fast ion conductor layer on the material surface or grain boundaries.

[0035] Compared with the prior art, the present invention has the following beneficial effects: (1) The ion reconstruction and regeneration method for waste layered cathode materials described in this invention simultaneously achieves triple repair under mild conditions of ≤850℃ and ≤6h: lithium replenishment, reversal of the rock salt phase-oriented layered structure, and fast ion conductor coating. Unlike traditional recycling (≥900℃ / ≥10h) and the high energy consumption of existing ion reconstruction and regeneration technologies, the "one-pot" process of this invention effectively reduces the lithium replenishment reaction temperature and time, thereby reducing energy consumption.

[0036] (2) The ion reconstruction and regeneration method for waste layered cathode materials described in this invention addresses the problems of layered structure collapse and rock salt phase accumulation in cathode materials caused by battery cycling. Through zirconium doping and lattice perturbation, the nickel layer in the rock salt phase is opened to create lithium intercalation spaces, driving the correct repositioning of nickel / lithium ions and achieving directional ion reconstruction and O3 phase layered structure reconstruction. The strengthened transition metal-oxygen bonds improve structural stability, extend the material's service life, and enhance its reuse value.

[0037] (3) The ion reconstruction and regeneration method of the waste layered cathode material described in this invention addresses the problem that the capillary resistance of the grain boundary channel in the sol environment hinders the regenerator precursor from entering the particle interior. It introduces a stable gas bubbling technology to break the gas resistance at the channel opening, create instantaneous power to drive the sol to penetrate and replace the internal gas. At the same time, the bubbling effect can effectively disperse the soft agglomeration of nanoparticles, and comprehensively improve the range and efficiency of the regenerator on / between the primary particles.

[0038] (4) The ion reconstruction and regeneration method of the waste layered cathode material described in this invention uses lithium phosphorus zirconium oxygen regenerator with fast ion conductor characteristics to construct three-dimensional lithium ion channels on the surface and / or grain boundaries of the cathode material, thereby enhancing the lithium ion transport rate of the material and improving the electrochemical performance of the material.

[0039] (5) The ion reconstruction and regeneration method of the waste layered cathode material described in this invention can utilize the coating of fast ion conductors on the cathode material to remove residual alkali on the water washing surface, thereby shortening the process and reducing costs.

[0040] (6) The direct repair and regeneration method of ternary cathode recycled material described in this invention can utilize the coating of fast ion conductors on cathode material to isolate the contact between liquid and solid electrolytes and cathode material, reduce side reactions, and make the recycled material suitable for both liquid and solid batteries.

[0041] (6) The direct repair and regeneration method for ternary cathode recycled materials described in this invention has a short process, is simple to operate, and is suitable for large-scale production. This method provides a new approach for the low-energy, high-quality, and high-value green recycling and upgrading of waste layered cathode materials. Attached Figure Description

[0042] Figure 1 The X-ray diffraction patterns of Embodiment 1, Comparative Example 1, and Comparative Example 3 of the present invention are shown below. Figure 2 This is a scanning electron microscope image of the waste cathode material in Comparative Example 1 of the present invention. Figure 3 This is a scanning electron microscope image of the regenerated cathode material prepared in Example 1 of the present invention. Figure 4 The images shown are scanning transmission electron microscope (STEM) images of lithium phosphorus zirconium oxide on the surface and inside of the regenerated particles in Example 1 of this invention, and a zirconium elemental distribution map. Figure 5 These are scanning transmission electron microscope images of the near-surface of typical grains in Example 1 and Comparative Example 1 of the present invention. Figure 6 The above diagram shows the charging and discharging effects of solid-state batteries used as positive electrodes in Embodiment 1 and Comparative Examples 1 and 5 of this invention.

[0043] Figure 7 The above diagram shows the charging and discharging effects of liquid batteries using Embodiment 1 and Comparative Examples 1 and 5 as positive electrodes. Detailed Implementation

[0044] The present invention will be described in detail below through specific embodiments to facilitate a better understanding of the invention. However, the following embodiments do not limit the scope of the invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0045] This invention relates to a method for the ion reconstruction and regeneration of waste layered cathode materials. It utilizes a stable gas bubbling technique to uniformly disperse waste cathode black powder in a regenerator precursor suspension. Targeting units in the regenerator target and reconstruct heterogeneous phases (non-layered phases) such as spinel, rock salt, and disordered phases in the waste layered cathode material, opening channels for lithium ions to enter the crystal lattice. This achieves cathode lattice structure repair and the construction of a fast ion conductor network at the surface and interface, enabling comprehensive lithium replenishment and layered structure repair from the surface to the core of the cathode material. Simultaneously, conductive units in the regenerator form a fast ion conductor coating on the cathode material surface or grain boundaries, enhancing intergranular contact and improving the ionic conductivity of the cathode material. This significantly improves the specific capacity, cycle stability, and rate performance of the regenerated cathode material in all-solid-state batteries, polymer gel batteries, and liquid batteries, thereby enhancing the utilization value of the regenerated cathode material.

[0046] In each embodiment, the waste layered cathode black powder used is prepared through the following steps: First, retired liquid lithium-ion pouch batteries are safely disassembled to separate the cathode sheets; then, organic matter and residual electrolyte are removed by sintering; finally, high-purity ternary cathode black powder is obtained through processes such as powder removal, sieving, acid washing (to remove fluorides), and drying, which is then used as a raw material for subsequent recycling. Specific steps can also be found in the literature. [Adv. Funct. Mater. 2025, e13772] .

[0047] Example 1 S1. Add 20 mL of anhydrous ethanol to the reactor and heat the reactor to 40 °C. Weigh 0.0318 g of LiH2PO4 and 0.057 g of Zr(NO3)4·5H2O (the molar ratio of lithium, phosphorus and zirconium is 2.2:2.2:1) and add them to the ethanol solvent from both ends of the reactor. Seal the bottle and place it on a magnetic stirrer. Stir the mixture at 50 °C (T1) and 600 rpm for 2 h to form a uniform suspension.

[0048] S2. The suspension obtained in S1 is heated to 80℃ (T2), and then 2g of waste lithium nickel cobalt manganese oxide cathode black powder (chemical formula Li) is added under continuous nitrogen gas purging. x Ni 0.8 Co 0.1 Mn 0.1 O2, 0.5≤ x<1) Slowly add it to the suspension and stir continuously for 8 hours to ensure that the regenerant precursor fully covers the surface and interior of the cathode material particles, thus obtaining a mixture of the two.

[0049] S3. Stop the nitrogen supply and open both valves of the reactor. Heating at 85℃ (T3) allows the ethanol in the mixture to completely evaporate. During the above process, ensure T1 < T2 < T3. The reactor is then transferred to a 90℃ oven for further drying to remove any remaining liquid, yielding a mixed powder of the waste cathode and the regenerator precursor.

[0050] S4. Place the dried mixed powder in a crucible and spread it evenly. Place the crucible in a tube furnace and calcine it in an oxygen atmosphere: raise the temperature to 750℃ at a heating rate of 3℃ / min and hold it at this temperature for 1 hour. After calcination, remove the sample, cool it to room temperature, and sieve it to obtain a 1.5wt% lithium phosphorus zirconium oxygen-coated recycled nickel cobalt manganese oxide cathode material.

[0051] Example 2 The difference between this embodiment and Embodiment 1 is that in S1, 0.0625g of LiH2PO4 and 0.1104g of Zr(NO3)4·5H2O are weighed and reacted to obtain a recycled lithium nickel cobalt manganese oxide cathode material with a lithium phosphorus zirconium oxygen coating of 3wt%.

[0052] Example 3 The difference between this embodiment and Example 1 is that in S1, 0.1035g of LiH2PO4 and 0.1835g of Zr(NO3)4·5H2O are weighed and reacted to obtain a recycled lithium nickel cobalt manganese oxide cathode material with a lithium phosphorus zirconium oxygen coating of 5wt%.

[0053] Example 4 The difference between this embodiment and Embodiment 1 is that in S1, 0.207g of LiH2PO4 and 0.367g of Zr(NO3)4·5H2O are weighed and reacted to obtain a recycled lithium nickel cobalt manganese oxide cathode material with a lithium phosphorus zirconium oxygen coating of 10wt%.

[0054] Example 5 The difference between this embodiment and Example 1 is that in S1, 0.021g LiH2PO4 and 0.057g Zr(NO3)4·5H2O are simultaneously added to a reactor containing 20ml of anhydrous ethanol to obtain 0.03g of lithium-phosphorus-zirconium oxygen regenerator. The molar ratio of lithium, phosphorus, and zirconium is 1.5:1.5:1.

[0055] Example 6 The difference between this embodiment and Embodiment 1 is that in S1, 0.0414g of LiH2PO4 and 0.057g of Zr(NO3)4·5H2O are simultaneously added to a reactor containing 20ml of anhydrous ethanol to obtain 0.03g of lithium-phosphorus-zirconium oxygen regenerator. The molar ratio of lithium, phosphorus, and zirconium is 3:3:1.

[0056] Example 7 The difference between this embodiment and Embodiment 1 is that: in S1, the temperature T1 is 90℃; in S2, the temperature T2 is 75℃; and in S3, the temperature T3 is 60℃. That is, T1 > T2 > T3.

[0057] Example 8 The difference between this embodiment and Embodiment 1 is that the temperatures T1 in S1, T2 in S2, and T3 in S3 are all 80℃. That is, T1=T2=T3.

[0058] Example 9 The difference between this embodiment and Embodiment 1 is that in S2, 2g of waste lithium cobalt oxide cathode black powder (chemical formula Li) is added. x CoO2, 0.5≤ x <1), finally a regenerated lithium cobalt oxide cathode material with a lithium phosphorus zirconium oxide coating of 1.5 wt% was obtained.

[0059] Example 10 The difference between this embodiment and Embodiment 1 is that in S2, 2g of waste lithium-rich manganese-based cathode black powder (chemical formula LiNi) is added. 0.5 Co 0.2 Mn 0.3 O2, 0.5≤ x <1), finally a regenerated lithium-rich manganese-based cathode material with a lithium phosphorus zirconium oxygen coating of 1.5 wt% was obtained.

[0060] Comparative Example 1 The unregenerated lithium nickel cobalt manganese oxide cathode black powder, that is, the cathode powder obtained by the recycling plant through a standardized process (including battery disassembly, electrode separation, crushing, etc.), is not processed in steps S1-S4 and is used as a comparative example of Examples 1-8.

[0061] Comparative Example 2 The difference between this comparative example and Example 1 is that in S1, 0.049g of LiH2PO4 and 0.0181g of Zr(NO3)4·5H2O were weighed (the molar ratio of lithium, phosphorus, and zirconium was 2.2:2.2:1). A recycled lithium nickel cobalt manganese oxide cathode material with a lithium-phosphorus-zirconium-oxygen coating of 0.5wt% was finally obtained, serving as a comparative example for Examples 1-4.

[0062] Comparative Example 3 The difference between this comparative example and Example 1 is that nitrogen gas is not introduced throughout S2. This serves as a comparative example to Example 1.

[0063] Comparative Example 4 The difference between this comparative example and Example 1 is that in S1, only 0.0318g of LiH2PO4 was weighed. The final result was a recycled lithium nickel cobalt manganese oxide cathode material obtained solely from Li / P source remediation, which served as the comparative example of Example 1.

[0064] Comparative Example 5 Commercial lithium nickel cobalt manganese oxide cathode materials, without S1-4 treatment, are used as comparative examples in Examples 1-8.

[0065] Comparative Example 6 The unregenerated lithium cobalt oxide cathode black powder, i.e. the cathode powder obtained from the recycling plant through a standardized process (including battery disassembly, electrode separation, crushing, etc.), is not processed in steps S1-S4 and is used as a comparative example of Example 9.

[0066] Comparative Example 7 The unregenerated lithium-rich manganese-based cathode black powder, i.e. the cathode powder obtained from the recycling plant through a standardized process (including battery disassembly, electrode separation, crushing, etc.), is used as a comparative example of Example 10 without the processing of steps S1-S4.

[0067] Comparative Example 8 The lithium cobalt oxide cathode black powder was mixed uniformly with lithium acetate, nickel acetate, and phosphorus pentoxide using a liquid-phase reaction method. The mass fractions of the latter three were 5%, 0.1%, and 3%, respectively. The mixture was then heat-treated at 600℃ for 20 hours in an oxygen atmosphere to obtain regenerated lithium cobalt oxide cathode material.

[0068] Solid-state battery assembly: In the above embodiments and comparative examples, the positive electrode material, Li6PS5Cl electrolyte, and conductive carbon black C65 were uniformly mixed at a mass ratio of 70:30:3 to form a composite positive electrode material. In an argon-atmospheric glove box, 80 mg of Li6PS5Cl was weighed as the electrolyte layer for the solid-state battery, and 10 mg of the composite positive electrode material was added as the positive electrode, with nickel foam as the current collector. A sulfide solid-state battery was assembled using a Li-In alloy as the negative electrode. Long-term cycle performance at 0.5C was tested within a voltage range of 2.6–4.3 V (vs. Li), and the results of capacity, coulombic efficiency, etc., were compared.

[0069] Assembly of polymer gel batteries: First, a ternary cathode material, conductive carbon black, and polyvinylidene fluoride binder were mixed to form a slurry, which was then coated onto an aluminum foil current collector and vacuum dried. A lithium metal anode was roll-pressed onto a copper foil. Subsequently, a polyoxyethylene gel electrolyte was prepared: polyoxyethylene and lithium salt were dissolved in a solvent and cast into a film. After the solvent evaporated to form a self-supporting film, it was immersed in a liquid electrolyte for activation, absorbing the electrolyte to form a gel electrolyte with high ion conductivity. In an argon-filled glove box, the cathode, polymer electrolyte film, and anode were stacked sequentially and hot-pressed (65℃, 8MPa) to ensure device adhesion. Finally, the device was encapsulated in an aluminum-plastic flexible package. After three cycles of activation at 0.1C within a voltage range of 3-4.3V (vs. Li), long-term cycling performance at 0.5C was tested, and results such as capacity and coulombic efficiency were compared.

[0070] Assembly of liquid batteries: The above embodiments and comparative examples obtained positive electrode materials, conductive carbon black Super P, and N-methylpyrrolidone solution of polyvinylidene fluoride were mixed uniformly in a mass ratio of 8:1:1 to prepare positive electrode slurry, which was then coated, dried, and rolled to obtain positive electrode sheets. The prepared positive electrode sheets, silicon-carbon negative electrode, separator, and electrolyte were assembled into coin cells for electrochemical performance testing. The separator used was Celgard 2400, and the electrolyte consisted of a mixed solution of 1M LiPF6, ethylene carbonate and methyl ethyl carbonate (volume ratio 7:3), and 2.0 wt% vinylene carbonate. After three cycles of activation at 0.1C within a voltage range of 3-4.3V (vs. Li), long-term cycle performance at 0.5C was tested, and the capacity, coulombic efficiency, and other results were compared.

[0071] (1) Examining the physicochemical characteristics of the layered cathode materials obtained in the examples and comparative examples. X-ray diffraction was performed on Example 1 (regeneration treatment), Comparative Example 1 (waste materials), and Comparative Example 3 (nitrogen-free bubbling-assisted regeneration). Figure 1 Characterization. The results showed that all three maintained R-3m Layered structure space group, but the intensity ratio of the (003) / (104) crystal plane diffraction peaks in Example 1 is ( I (003) / I (104) The intensity ratio was significantly higher than that of Comparative Example 1. This increase in intensity directly confirms that the regeneration process effectively achieved the transformation from rock salt phase to layered phase, thereby suppressing lithium-nickel mixing caused by heterogeneous phases. Furthermore, Example 1 ( I (003) / I (104) =1.9) and Comparative Example 3 ( I (003) / I (104) =1.7) compared to waste materials (I (003) / I (104) Comparative data (=0.9) demonstrates that introducing nitrogen gas during the regeneration process can significantly improve the repair rate of layered structures. The microstructures of Example 1 and Comparative Example 1 were compared using scanning electron microscopy. Figure 2 ,3), it was found that both maintained a complete spherical secondary particle structure. Figure 3 and Figure 4 The results show that zirconium, as a regenerator, exhibits a high abundance distribution in the recycled cathode material, not only uniformly coating the particle surface but also successfully penetrating into the interstitial spaces within the particles. More importantly, as... Figure 5 As shown, comparing the typical near-surface structure of the grains in Example 1 and Comparative Example 1, it was found that the grains in Example 1 exhibited a complete layered structure, which contrasted sharply with the rock salt phase tens of nanometers thick on the surface of the grains in Comparative Example 1. This significant microscopic difference fully verifies the remarkable effectiveness of this invention in heterogeneous phase reconstruction and layered structure recovery of waste cathode materials. Inductively coupled plasma mass spectrometry was used to detect the elemental composition of Examples 1-4 and Comparative Examples 1-3,5, and the relevant results are shown in Table 1. The data show that: (1) the lithium phosphorus zirconium oxygen regenerator can effectively replenish the lithium content, and the replenishment efficiency is positively correlated with the amount of regenerator added; (2) the difference in lithium content improvement between Example 1 and Comparative Example 3 indicates that the introduction of nitrogen gas in the regeneration process can significantly improve the lithium replenishment effect; (3) copper, aluminum and other current collector residual impurities were detected on the surface of the waste materials (due to the limitations of the recycling process). As a fast ion conductor, the lithium phosphorus zirconium oxygen regenerator has an intrinsic lithium-ion conductivity of 2.3 × 10⁻⁶. -5 S / cm. The cathode material repaired and regenerated based on this material (Example 1) achieved a significant improvement in lithium-ion conductivity, with the conductivity increasing by nearly two orders of magnitude, even surpassing the commercial cathode material in Comparative Example 5 (Table 2). Furthermore, the data in Table 3 show that the residual alkali content of Example 1 was also significantly reduced compared to the waste cathode (Comparative Example 1) and the commercial cathode (Comparative Example 5).

[0072] (2) Examine the electrochemical performance of the layered cathode materials obtained in the examples and comparative examples. Comparing the long-cycle performance of solid-state batteries assembled from recycled nickel-cobalt-manganese lithium oxide cathode materials, waste cathode materials, and commercial cathode materials obtained through different regenerant contents and treatment processes, the data results show that: Too low a regenerant content (0.5%) fails to achieve complete coating of the particle surface or sufficient penetration into the grain boundaries, thus hindering lithium-ion replenishment of the lithium source and zirconium-ion reconstruction of the heterogeneous phase. Although this content shows some modification effect compared to directly using waste cathodes, its first-cycle discharge specific capacity and cycle stability are lower than those of sulfide solid-state batteries assembled using uncoated original cathodes. An appropriate regenerant content (1.5%) achieves optimal lithium replenishment and interface reconstruction effects, significantly improving lithium-nickel mixing, reconstructing the heterogeneous phase into a stable layered structure, and constructing a three-dimensional conductive network in the cathode, promoting lithium-ion diffusion and capacity release. Its electrochemical performance is far superior to waste cathodes and uncoated cathodes. Figure 6 (See Table 4); a higher regenerator content (≤10%), while not as effective as 1.5%, still provides good lithium replenishment and interface reconstruction. Furthermore, the performance comparison between Example 1 and Comparative Example 4 in Table 4 shows that the synergistic effect of Zr, P, and Li sources significantly improves the electrochemical performance of the material, while using only P and Li sources is ineffective. This result clarifies the crucial role of the Zr source in the regeneration process. Regenerated nickel-cobalt-manganese lithium oxide cathode materials not only exhibit excellent electrochemical performance in solid-state batteries, but also serve as polymer gel batteries and liquid batteries (…). Figure 7 When the positive electrode is used, it also exhibits high discharge specific capacity and cycle stability (Table 5).

[0073] The key process methods for regeneration were adjusted, including: the molar ratio of lithium, phosphorus, and zirconium in S1 (Examples 1 and 5 / 6), the temperature rise and fall sequence of S1-S3 (Examples 1 and 7 / 8), and whether nitrogen was introduced in S2 (Examples 1 and Comparative Example 3). As shown in Table 6, after testing the electrochemical performance of the relevant examples, it was found that, under the premise of ensuring that the obtained regenerator conforms to the target chemical formula, the process parameters can still achieve efficient regeneration of waste cathode materials: (1) The molar ratio of lithium, phosphorus, and zirconium in S1 can achieve good regeneration effect in the range of 1.5-3:1.5-3:1, but the molar ratio of the three elements is 2.2: 2.2:1 can further improve the electrochemical performance of the regenerated cathode in the battery; (2) The regeneration performance obtained when T1 < T2 < T3 in S1-3 is better than T1 > T2 > T3 and T1 = T2 = T3; (3) When nitrogen is not introduced in S2, the regeneration effect of the waste cathode material is not good, and the performance improvement of the regenerated nickel cobalt manganese oxide cathode material is extremely limited (first cycle discharge capacity < 165 mAh / g, 200 cycle retention rate < 85%). On the contrary, the electrochemical performance of the regenerated cathode material can be greatly improved after the introduction of the stabilizing gas. This phenomenon is mainly attributed to the gas circulation in the mixture promoting the liquid to penetrate into the gap between the cathode particles, thereby fully replenishing the lithium element in the material and improving the lithium-nickel mixing.

[0074] Besides lithium nickel cobalt manganese oxide, the lithium phosphorus zirconium oxygen ion reconstruction and regeneration method of the present invention is also applicable to waste lithium-rich manganese-based and lithium cobalt oxide cathode materials. It can effectively restore their layered structure, improve lithium-ion transport kinetics, and significantly enhance the electrochemical performance of the assembled solid-state battery (Table 4). Furthermore, by comparing the two regenerated lithium cobalt oxide cathode materials prepared by Example 1 and the simple liquid-phase mixing method (Comparative Example 8), it can be found that the mixing method used in the former, along with its corresponding raw material ratios, reaction temperature, and time, enables the regenerated cathode to exhibit superior electrochemical performance in solid-state batteries. In contrast, the regenerated cathode obtained by the latter exhibits poor performance in solid-state batteries and is therefore unsuitable for solid-state battery systems with strict requirements for interfacial transport processes.

[0075] Among them, the solid-state battery assembled in Example 1 (1.5% regenerator) had an initial discharge specific capacity of 213.1 mAh / g, an initial coulombic efficiency of 82%, and a capacity retention of 90% after 200 cycles in a voltage range of 2.6-4.3V (vs. Li) and a rate of 0.5C. The battery assembled directly using waste cathode (Comparative Example 1) had an initial discharge specific capacity of only 89 mAh / g, an initial coulombic efficiency of 51%, and a capacity retention of only 20% after 200 cycles. The battery assembled in Comparative Example 5 (uncoated original cathode) had an initial discharge specific capacity of 158.9 mAh / g, an initial coulombic efficiency of 70%, and a capacity retention of 70% after 200 cycles, representing the average performance level of commercial cathode materials in solid-state batteries.

[0076] Table 1. Comparison of elemental contents between Examples 1-4 and Comparative Examples 1-3, 5

[0077] Table 2. Comparison of lithium-ion conductivity between Example 1 and Comparative Examples 1 and 5

[0078] Table 3. Comparison of residual alkali content between Example 1 and Comparative Examples 1 and 5

[0079] Table 4. Comparison of electrochemical performance of solid-state batteries using Examples 1-4, 9-10 and Comparative Examples 1-2, 4, 6-8 as cathodes

[0080] Table 5. Comparison of electrochemical performance of solid, polymer gel, and liquid lithium batteries used as positive electrodes in Example 1 and Comparative Examples 1 and 5

[0081] Table 6. Comparison of electrochemical performance of solid-state batteries using Example 1, Examples 5-8 (with key process adjustments), and Comparative Example 3 as the positive electrode.

[0082] In summary, this invention provides a synergistic regeneration method for waste layered cathode materials. Through a "one-pot" process, it simultaneously achieves lithium replenishment, layered structure repair, and interface coating. The regeneration process leverages the deep penetration and ion reconstruction effect of the regenerating agent ions to fully restore the layered structure and form a fast-ion conductor layer on the particle surface and grain boundaries, significantly improving the ion mobility at the solid-solid interface. This substantially enhances the specific capacity, cycle life, and rate performance of all-solid-state, polymer gel, and liquid lithium-ion battery systems, which have high requirements for interface transport. This provides a new approach for the high-quality, high-value recycling and upgrading of waste cathode materials. Compared to unregenerated materials and commercially available layered cathode materials, this regenerating agent can significantly improve the discharge specific capacity, electrochemical stability, and cycle life of the material in solid-state and liquid batteries. This method has advantages such as a simple process flow, mild lithium replenishment conditions, and low cost, and has the potential for large-scale application in various battery types.

[0083] It should be noted that: 1. The embodiments of the present invention are only used to illustrate the technical principles and do not constitute a limitation on the specific implementation methods; 2. The protection scope of this invention patent covers various specific process paths for realizing regeneration. Specifically, in step S1, any feeding method that can achieve uniform mixing of the phosphorus-lithium source and zirconium source powders (including but not limited to adding simultaneously or separately); in the synthesis of the regenerant precursor, any method that can form the required active precursor (including but not limited to hydrothermal method, coprecipitation method, etc.); and in step S3, any drying method that can effectively remove the solvent of the mixed solution (including but not limited to evaporation first and then drying, drying first and then evaporation, direct drying, etc.), as long as it follows the core step process and composition design of this invention, belongs to the protection scope of this patent and can have a positive regeneration and repair effect on the waste cathode material. To achieve the optimal repair performance, the following optimized process combination is recommended: using the sol-gel method, adding raw materials simultaneously in the S1 solvent, evaporating first and then drying the S3 mixed solution, Li:P:Zr = 2.2:2.2:1, T1 < T2 < T3, and introducing nitrogen in S2.

[0084] 3. After comprehensive parameter optimization, the performance of the lithium battery using the regenerated electrode material of this invention is expected to be more significantly improved.

[0085] For those skilled in the art, any obvious modification or equivalent replacement made to the described embodiments without departing from the core principle of this invention shall fall within the protection scope defined by the claims.

Claims

1. A method for ion reconstruction and regeneration of positive electrode material in waste batteries, characterized in that, Waste cathode black powder is uniformly dispersed in a regenerator precursor suspension using a gas bubbling method to achieve the coating of the regenerator precursor on the surface of the black powder particles and its penetration into the pores inside the particles; then, further calcination treatment is carried out to achieve ion reconstruction of the cathode material in the waste battery using the regenerator.

2. The method according to claim 1, wherein the method is characterized by, The regenerant precursor suspension is obtained by simultaneously adding powder containing lithium, phosphorus and zirconium sources to a preheated organic solvent and mixing it thoroughly; wherein, the molar ratio of lithium, phosphorus and zirconium in the precursor suspension is 1.5-3:1.5-3:

1.

3. The method according to claim 2, wherein the ion reconstitution regeneration method of the positive electrode material of the waste battery is characterized by, The liquid-solid mass ratio of the regenerator precursor suspension to the waste cathode black powder is 5:1-20:

1.

4. The method according to claim 3, wherein the ion reconstitution regeneration method of the positive electrode material of the waste battery is characterized by, The phosphorus-containing lithium source powder can be obtained directly from one or more of lithium dihydrogen phosphate, lithium phosphate, lithium hexafluorophosphate and their derivatives, or it can be prepared by reacting zirconium phosphate with one or more lithium salt substances, wherein the lithium salt substances are lithium hydroxide, lithium carbonate and lithium oxide. The zirconium source powder is derived from one or more of zirconium nitrate hydrate, zirconium oxynitrate hydrate, zirconium oxychloride hydrate, and zirconium oxysulfate hydrate; the organic solvent is one or more of anhydrous ethanol, methanol, propanol, n-propanol, isopropanol, ethylene glycol, and glycerol.

5. The ion reconstruction and regeneration method for positive electrode materials in waste batteries according to any one of claims 1-4, characterized in that, S1. Heat the organic solvent to temperature T1, and then simultaneously add phosphorus-containing lithium source and zirconium source powder to the organic solvent, and stir until it reaches a suspension state to obtain the regenerator precursor; S2. Heat the regenerator precursor suspension to temperature T2, then introduce a stabilizing gas under continuous stirring, and add waste positive electrode black powder to fully disperse and evenly obtain a mixed solution. Stir for 12 hours under temperature T2 and continuous introduction of stabilizing gas to achieve the coverage of the regenerator precursor on the surface of the black powder particles and the penetration into the pores inside the particles. S3. After the above reaction, stop the introduction of stabilizing gas, evaporate the mixture obtained in S2 at temperature T3, and further dry to remove liquid residue to obtain a mixed powder of waste positive electrode and regenerator precursor. S4. The mixed powder obtained above is calcined at high temperature to achieve regenerant penetration and in-situ structural regeneration of waste cathode particles. After cooling, it is sieved to obtain the in-situ repaired and regenerated layered cathode material.

6. The method according to claim 5, wherein the ion reconstitution regeneration method of the positive electrode material of the waste battery is characterized by, The stabilizing gas is one or more of oxygen, nitrogen, and air.

7. The method according to claim 5, wherein the ion reconstitution regeneration method of the positive electrode material of the waste battery is characterized by, The temperature range of T1 is 30-55℃, the temperature range of T2 is 40-85℃, and the temperature range of T3 is 70-100℃; The drying temperature range in S3 is 60-90℃, the drying time is 5-12h, and the drying atmosphere is air and / or oxygen. The high-temperature calcination in S4 involves heating at a rate of 1-10℃ / min to 650-850℃, holding for 0.5-6 hours, and using oxygen in the sintering atmosphere.

8. The method for ion reconstitution regeneration of positive electrode material in waste battery according to claim 1, 2 or 5, characterized in that, The waste cathode black powder is waste layered cathode black powder extracted from all-solid, polymer gel, and liquid lithium batteries.

9. An application of the method according to claim 1, characterized in that, The method of claim 1 obtains the application of the positive electrode material in the ion-reconstructed recycled waste battery as a polymer gel lithium battery and a liquid lithium battery.

10. A regenerated lithium battery, comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that: The positive electrode contains the positive electrode material from the waste battery that has been regenerated by the ion reconstruction method described above.

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