Method for preparing high-performance electrolyzed water anode catalyst by recycling anode materials of waste lithium iron phosphate batteries and high-nickel ternary lithium ion batteries

Abstract

The invention relates to a method for preparing a high-performance electrolyzed water anode catalyst by recycling anode materials of waste lithium iron phosphate batteries and high-nickel ternary lithium ion batteries, which comprises the following steps: selectively leaching lithium in lithium iron phosphate and high-nickel ternary anode black powder to obtain lithium-containing leachate and residual solid powder; the residual solid powder is added into a composite solvent composed of citric acid and glucose, and a leaching solution is obtained; mixing the lixivium according to a certain nickel-iron molar ratio to obtain a composite lixivium; soaking the pretreated foamed nickel into the composite leaching solution, and dropwise adding an oxalic acid solution into the composite leaching solution to obtain a self-supporting NiFe-based catalyst intermediate; or directly dropwise adding an oxalic acid solution into the composite leachate to obtain a powder NiFe-based catalyst intermediate; placing the intermediate in a KOH solution, and then washing and drying to obtain the catalyst. Compared with the prior art, the invention provides a brand new battery material recycling method which is simple to operate, low in cost and low in energy consumption.

Description

Technical Field

[0001] This invention relates to the field of lithium battery recycling technology, specifically to a method for preparing high-performance water electrolysis anode catalysts by recycling cathode materials from waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries. Background Technology

[0002] With the rapid development of the new energy industry, the large-scale application of lithium-ion batteries in electric vehicles and energy storage has led to a surge in the total amount of waste batteries. However, as lithium-ion batteries become more widespread and are replaced, the issues of disposal and resource recycling of retired batteries are becoming increasingly prominent. Improper disposal of retired batteries can cause soil and water pollution due to the heavy metals (such as nickel and cobalt) and electrolytes (such as lithium hexafluorophosphate) they contain, threatening ecological and environmental safety. Furthermore, lithium-ion battery cathode materials are rich in high-value metals such as lithium, iron, nickel, cobalt, and manganese; improper disposal of these waste batteries will also inevitably lead to the waste of these metal resources.

[0003] Currently, the main processes for recycling waste lithium iron phosphate batteries and ternary lithium-ion batteries are divided into dry metallurgy and hydrometallurgy. Dry metallurgy decomposes organic matter and reduces metal oxides through high-temperature roasting. While it can handle mixed battery types, it is energy-intensive and generates large amounts of toxic gases such as CO2, HF, and furans, with a metal recovery rate of less than 85%. Hydrometallurgical processes typically begin with a leaching step, using leaching reagents to leach metal elements from the cathode material, followed by post-processing to obtain high-purity metal salts. Compared to pyrometallurgy, hydrometallurgy offers higher recovery efficiency, higher metal selectivity, and lower energy consumption. However, current hydrometallurgical processes primarily use inorganic strong acids (sulfuric acid, hydrochloric acid, and nitric acid) as leaching reagents. This process generates large amounts of acidic waste liquid, posing a threat to the environment. Subsequent neutralization requires large amounts of alkaline solutions, leading to increased overall costs. More importantly, the complex processes for separating and purifying different metals also significantly increase recycling costs.

[0004] Given the high homology of active components (transition metal elements) between lithium-ion battery cathode materials and oxygen evolution reaction catalysts in water electrolysis, the extraction and reconstruction of the rich transition metal elements from recycled lithium-ion batteries to prepare high-efficiency electrocatalysts has become an effective strategy for resource recycling. While some studies have applied hydrometallurgical recycling technology to catalyst preparation (e.g., patents CN 110743528 A, CN 111659399 A, CN 120127261A), existing processes generally have significant drawbacks: firstly, high-purity metal salt intermediates must be obtained through multi-stage purification; secondly, secondary processing of the intermediates is required; and finally, complex catalytic material synthesis processes are necessary. This multi-step series mode not only significantly increases energy consumption and cost but also makes it difficult to balance the economic efficiency of the recycling process with the catalytic performance of the products. Furthermore, some processes do not separately recover high-value lithium elements, resulting in direct waste of these elements. Therefore, developing new resource-saving recycling processes that combine short processes, broad applicability, and recyclable leaching agents has become crucial for driving the development of this field.

[0005] Patent CN118621359A discloses a method for efficiently recovering nickel, cobalt, and manganese from retired lithium batteries to prepare electrocatalysts. This method uses inorganic acids and reducing agents as additives to obtain a leachate rich in valuable metals. Then, ammonium fluoride and urea are added to the leachate as co-reactants and precipitants for a hydrothermal reaction. The hydrothermal decomposition of urea provides an alkaline environment, and under the action of ammonium fluoride, metal ions and anions in the solution react to generate a catalyst precursor with a regular morphology, which is then phosphated in one step to obtain a water electrolysis catalyst. The hydrometallurgical leachate used in this invention is inexpensive, non-toxic, and harmless. The prepared electrocatalyst has the characteristics of regular morphology, large specific surface area, and stable catalytic performance, showing good application prospects. However, this invention directly co-leaches lithium and other transition metal elements to synthesize the catalyst, without separately recovering the high-value lithium element, resulting in direct waste of this element. Furthermore, both the hydrothermal reaction and the phosphating process of the catalyst precursor in this invention require high-temperature conditions, significantly increasing the energy consumption for recycling retired materials. Furthermore, the catalyst preparation process introduces additional chemical reagents such as urea, ammonium fluoride, and sodium hypophosphite, which not only increases the overall process cost but also introduces additional waste liquid treatment requirements. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing high-performance water electrolysis anode catalysts by recycling cathode materials from waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries. The process conditions are mild and the procedure is simple. The prepared NiFe-based catalyst exhibits excellent OER catalytic activity and stability.

[0007] The objective of this invention can be achieved through the following technical solution: a method for preparing a high-performance anode catalyst for water electrolysis by recycling cathode materials from waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries, comprising the following steps:

[0008] (1) Discharge the recycled lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries completely, and disassemble and separate the lithium iron phosphate and high-nickel ternary cathode black powder.

[0009] (2) Selectively leach lithium from the lithium iron phosphate and high-nickel ternary cathode black powder separated in step (1) to obtain lithium-containing leachate and residual solid powder.

[0010] (3) The residual solid powder recovered in step (2) is added to a composite solvent composed of citric acid and glucose, and the mixture is stirred continuously to carry out the leaching reaction. After the reaction is completed, the leachate is obtained.

[0011] (4) The leachate obtained in step (3) is uniformly mixed according to a certain nickel-iron molar ratio to obtain a composite leachate;

[0012] (5) The pretreated nickel foam is immersed in the composite leachate obtained in step (4), and oxalic acid solution is added dropwise to the composite leachate. The mixture is stirred thoroughly at room temperature to carry out the reaction. After the reaction is completed, the nickel foam is washed and dried to obtain a self-supporting NiFe-based catalyst intermediate; or, oxalic acid solution is added dropwise directly to the composite leachate obtained in step (4), and the mixture is stirred thoroughly at room temperature to carry out the reaction. After the reaction is completed, the reaction product is collected, centrifuged, washed and dried to obtain a powdered NiFe-based catalyst intermediate.

[0013] (6) Place the self-supported NiFe-based catalyst intermediate or powdered NiFe-based catalyst intermediate in KOH solution, then wash and dry to obtain the self-supported NiFe-based catalyst or powdered NiFe-based catalyst.

[0014] Preferably, in step (5), the pretreated nickel foam is immersed in the composite leachate obtained in step (4), and oxalic acid solution is added dropwise to the composite leachate. The mixture is stirred thoroughly at room temperature to carry out the reaction. After the reaction is completed, the nickel foam is washed and dried to obtain a self-supporting NiFe-based catalyst intermediate.

[0015] (6) The self-supporting NiFe-based catalyst intermediate was placed in KOH solution, then washed and dried to obtain the self-supporting NiFe-based catalyst.

[0016] More preferably, the remaining reaction product from step (5) is collected, centrifuged, washed and dried to obtain a powdered NiFe-based catalyst intermediate, which is dissolved in KOH solution, ultrasonically treated and centrifuged to separate the precipitate, washed with ethanol and dried, and ground to obtain a powdered NiFe-based catalyst.

[0017] This invention employs a green and low-cost citric acid-glucose mixed solvent to construct a leaching system, achieving efficient leaching of transition metals such as Fe, Ni, Mn, and Co under mild conditions. Simultaneously, the method utilizes a simple and efficient seed-assisted growth method to construct a high-performance, self-supporting NiFe-based oxygen evolution reaction catalyst in situ within the leaching solution, while simultaneously collecting the powdered NiFe-based catalyst, thus avoiding the intermediate separation and purification steps required in traditional processes. This invention is simple to operate, environmentally friendly, and significantly reduces wastewater treatment pressure. Furthermore, by directly using the leaching solution for in-situ catalyst synthesis, this invention reduces recovery processes and costs, demonstrating potential for large-scale application.

[0018] Preferably, the nickel content in the cathode material of the high-nickel ternary lithium-ion battery is ≥50% by mass.

[0019] Preferably, the high-nickel ternary cathode black powder is derived from one or more ternary lithium-ion batteries that meet high-nickel standards.

[0020] Preferably, in step (2), lithium is selectively leached from the lithium iron phosphate and high-nickel ternary cathode black powder separated in step (1) using chemical or electrochemical methods.

[0021] More preferably, the chemical method includes the following steps: adding lithium iron phosphate and an oxidant to deionized water and leaching at room temperature for 20–120 min.

[0022] More preferably, the solid-liquid ratio of the oxidant to deionized water is 0.005g:1mL to 0.1g:1mL.

[0023] More preferably, the solid-liquid ratio of lithium iron phosphate to deionized water is 0.01g:1mL to 0.2g:1mL.

[0024] More preferably, the stirring speed during leaching is 300-800 rpm, and after leaching, centrifugation is used to separate the lithium-containing leachate and delithiated lithium iron phosphate black powder.

[0025] More preferably, the oxidant comprises sodium persulfate.

[0026] More preferably, the electrochemical method includes the following steps: mixing high-nickel ternary cathode black powder and polyvinylidene fluoride (PVDF) at a mass ratio of 20:1 to 30:1, then adding the mixture to N-methylpyrrolidone (NMP) reagent to prepare a slurry; stirring evenly; and then coating the slurry onto graphite paper or carbon paper, with an active material loading of 2 to 20 mg / cm³. 2 After drying, the dried graphite paper or carbon paper is cut into a suitable size to serve as the positive electrode. A platinum sheet or graphite paper of the same or similar size as the positive electrode is used as the negative electrode. A 0.1-1M sulfate solution or carbonate solution is used as the electrolyte. A voltage of 1-2.5V is applied for electrochemical delithiation for 10-180 minutes, with a stirring speed of 200-800 rpm. A lithium-containing leachate is then obtained. The black powder on the graphite paper or carbon paper is scraped off, ground, and washed with water and ethanol to obtain the lithium-delithiated high-nickel ternary positive electrode black powder.

[0027] More preferably, the drying conditions are vacuum drying at 75-85°C for 10-14 hours, and more preferably vacuum drying at 80°C for 12 hours.

[0028] More preferably, the electrolyte is a sodium sulfate solution, a potassium sulfate solution, or a sodium carbonate solution.

[0029] Preferably, the lithium-containing leachate obtained in step (2) is successively evaporated, concentrated, purified, and a crystallizing additive is introduced to generate a lithium compound precipitate that is insoluble in water, and finally a crystalline lithium salt is obtained.

[0030] More preferably, the crystallizing additive is sodium carbonate, sodium phosphate, or sodium hydroxide, and the corresponding crystalline lithium salts are lithium carbonate, lithium phosphate, or lithium hydroxide, respectively.

[0031] More preferably, the lithium compound precipitate is filtered, washed, and dried to obtain a crystalline lithium salt.

[0032] More preferably, the purification method involves adding a purifying agent to the concentrated liquid obtained by evaporation and concentration, adjusting the pH to convert the impurity metal ions into insoluble precipitates, and obtaining a purified lithium-containing solution after solid-liquid separation.

[0033] In this invention, the lithium-containing leachate obtained in step (2) can be concentrated by evaporation to increase the concentration of lithium ions in the solution, thereby helping to improve the recovery efficiency of lithium. Subsequently, a purifying agent (such as sodium hydroxide solution) is added to the concentrated solution to adjust the pH of the system, thereby reducing the concentration of impurity metal ions (such as Fe). 3+The lithium ions are converted into an insoluble hydroxide precipitate. After solid-liquid separation, a purified lithium-containing solution is obtained. A crystallizing additive is introduced into this purified solution, which reacts with the lithium ions in the solution to form a lithium compound precipitate that is poorly soluble in water. During the reaction, conditions such as temperature, pH, and stirring rate are controlled to ensure the precipitation reaction proceeds fully. After the precipitate forms, the product is separated from the mother liquor by filtration, washing, and drying to obtain crystalline lithium salt.

[0034] In the alternative, the crystallization additive can be sodium carbonate, sodium phosphate, or sodium hydroxide, and the corresponding crystallization products are lithium carbonate, lithium phosphate, or lithium hydroxide, respectively.

[0035] Preferably, in the composite solvent described in step (3), the molar concentration of citric acid is 1.0 to 3.0 mol / L, the solid-liquid ratio of the residual solid powder to the leaching agent composite solvent is 5 g:1 L to 50 g:1 L, and the mass ratio of the residual solid powder to the reducing agent glucose is 5:1 to 1:1.

[0036] Preferably, the leaching temperature in step (3) is 60-90°C and the leaching time is 60-120 min.

[0037] Preferably, after the reaction in step (3) is completed, a leachate containing mainly iron and a small amount of other transition metal elements and a leachate containing mainly nickel and a small amount of other transition metal elements are obtained respectively.

[0038] In this invention, the leachate obtained by leaching the residual solid powder of lithium iron phosphate mainly contains iron and a small amount of other transition metal elements. The leachate obtained by leaching the residual solid powder of high-nickel ternary cathode black powder mainly contains nickel and a small amount of other transition metal elements.

[0039] Preferably, in step (3), the residual solid powder recovered in step (2) is added to a 1.0-3.0 mol / L citric acid solution, and glucose reducing agent is added to react. Under stirring, the temperature is raised to 60-90℃ and reacted for 60-120 min. After the reaction is completed, a leachate containing transition metal iron and a small amount of other transition metal elements and a leachate containing nickel and a small amount of other transition metal elements are obtained.

[0040] More preferably, the solvent for the citric acid solution is deionized water.

[0041] In this invention, for some high-nickel ternary cathodes, the leachate can also be used to separate some other non-nickel elements.

[0042] Preferably, the nickel-iron molar ratio in step (4) is 1:1 to 5:1.

[0043] In this invention, the iron-containing leachate and the nickel-containing leachate obtained in step (3) are mixed evenly according to a nickel-iron molar ratio of 1:1 to 5:1 to obtain a composite leachate.

[0044] Preferably, the solvent for the oxalic acid solution in step (5) is water, ethanol, or a mixture of alcohol and water.

[0045] More preferably, the alcohol in the alcohol-water mixture includes ethanol.

[0046] More preferably, the solvent for the oxalic acid solution is pure water.

[0047] Preferably, the molar ratio of oxalic acid to nickel ions in the composite leachate in step (5) is 5:1 to 20:1.

[0048] Preferably, the reaction time in step (5) is 60 to 120 minutes.

[0049] Preferably, the detergent for the foamed nickel in step (5) is ethanol.

[0050] Preferably, the drying temperature in step (5) is 60-80°C.

[0051] Preferably, the pretreatment method for nickel foam in step (5) includes ultrasonic treatment of nickel foam in HCl solution, organic solvent and deionized water in sequence.

[0052] In this invention, a certain geometric area of ​​nickel foam NF is cut and pretreated to remove the natural oxide layer and contaminants on the surface of the nickel foam.

[0053] More preferably, the organic solvent includes acetone and ethanol.

[0054] More preferably, the concentration of the HCl solution is 0.5–1.0 mol / L.

[0055] More preferably, the nickel foam is ultrasonically treated sequentially in HCl solution, organic solvent, and deionized water for 5–20 min.

[0056] Preferably, in step (5), the pretreated nickel foam is immersed in the composite leachate described in step (4), oxalic acid solution is added dropwise, and the mixture is stirred at room temperature for 60-120 min. After the reaction is completed, the reacted nickel foam is washed several times with anhydrous ethanol and then dried at 60°C to obtain a self-supporting NiFe-based catalyst intermediate.

[0057] Preferably, in step (6), the self-supporting NiFe-based catalyst intermediate is placed in KOH solution for reaction. After the reaction is completed, the reacted nickel foam is washed and dried to obtain the self-supporting NiFe-based catalyst.

[0058] More preferably, the molar concentration of the KOH solution is 0.5–5.0 mol / L; the reaction time is 30–60 min; and the drying temperature is 60–120 °C.

[0059] More preferably, the molar concentration of the KOH solution is 1.0 to 3.0 mol / L.

[0060] More preferably, the solvent for the KOH solution is deionized water.

[0061] More preferably, the solvent used for washing is ethanol.

[0062] Preferably, in step (6), the powdered NiFe-based catalyst intermediate is placed in KOH solution, ultrasonically treated, centrifuged to separate the precipitate, washed and dried, and then ground to obtain the powdered NiFe-based catalyst.

[0063] More preferably, the molar concentration of the KOH solution is 0.5–5.0 mol / L; the ultrasonic treatment time is 30–60 min; and the drying temperature is 60–120 °C.

[0064] More preferably, the molar concentration of the KOH solution is 1.0 to 3.0 mol / L.

[0065] More preferably, the solvent for the KOH solution is deionized water.

[0066] More preferably, the solvent used for washing is ethanol.

[0067] Preferably, the method for separating lithium iron phosphate and high-nickel ternary cathode black powder in step (1) includes high-temperature sintering, organic solvent cleaning or hot water bath stripping.

[0068] More preferably, the high-temperature sintering method is as follows: the separated lithium iron phosphate cathode and high-nickel ternary cathode are cut into small pieces, roasted in a muffle furnace to remove the binder and aluminum foil, and then ground and sieved to obtain raw material powder.

[0069] More preferably, the roasting temperature of the roasting treatment is 500-600℃; the roasting time is 30-60 min.

[0070] More preferably, the organic solvent cleaning method is as follows: the separated lithium iron phosphate cathode and high-nickel ternary cathode materials are respectively chopped and soaked in N,N-dimethylformamide, ultrasonicated at 65-75°C for 1.5-2.5 hours, and then sieved to obtain current collector fragments, conductive agent, lithium iron phosphate cathode material and high-nickel ternary cathode material. The cathode active material is dried and ground into powder to obtain lithium iron phosphate cathode black powder and high-nickel ternary cathode black powder.

[0071] More preferably, the ultrasound is performed at 70°C for 2 hours.

[0072] More preferably, the hot water bath stripping method is as follows: after cleaning the positive electrode sheet surface with the organic solvent dimethyl carbonate to remove by-reaction products and residual lithium salt electrolyte, the positive electrode sheet is obtained. The positive electrode material and current collector are separated by hot water immersion. The obtained positive electrode material is dried and ground into powder. The positive electrode material powder is collected and washed or heat-treated (to remove the binder polyvinylidene fluoride PVDF) with the organic solvent N-methylpyrrolidone and then dried to obtain retired lithium iron phosphate and high-nickel ternary positive electrode black powder.

[0073] This invention addresses three major problems in traditional waste lithium battery cathode material recycling processes: complex processes (requiring multiple steps such as acid leaching, separation, and purification), wastewater pollution (strong acid / alkali systems generate environmental burden), and high regeneration costs (multiple processes lead to increased energy consumption). It provides a method for recycling cathode materials from waste lithium iron phosphate batteries and ternary lithium-ion batteries to prepare high-performance water electrolysis anode catalysts.

[0074] This invention selectively leaches and extracts lithium before leaching transition metal ions (such as iron, nickel, cobalt, and manganese), thus achieving high-value utilization of lithium. Furthermore, this method uses an environmentally friendly citric acid-glucose system as the leaching agent to separately leach metal ions from pre-delithiated retired lithium iron phosphate and high-nickel cathode materials, obtaining Fe-rich lithium. 2+ and Ni 2+ The two leachates were mixed at a specific nickel-iron molar ratio to form a composite leachate. Oxalic acid solution was then added dropwise to the composite leachate to react and obtain a NiFe oxalate precursor. Finally, the precursor was converted by potassium hydroxide treatment to obtain a NiFe-based catalyst.

[0075] The hydrometallurgical leaching strategy based on citric acid-glucose adopted in this invention is low-cost, non-toxic, harmless, and environmentally friendly; the catalyst preparation process is mild (no high temperature or hydrothermal required), has few steps, and is simple, showing good potential for large-scale application; the prepared NiFe-based catalyst exhibits excellent OER catalytic activity and stability.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] 1. This invention provides a method for simultaneously recycling cathode materials from spent lithium iron phosphate batteries and ternary lithium-ion batteries to prepare high-performance anode catalysts for water electrolysis. A green, low-cost citric acid-glucose mixed solvent is used to leach transition metal elements from the cathode materials of spent lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries. A simple and efficient method is employed to prepare high-performance composite NiFe-based self-supporting electrodes and high-performance composite NiFe-based powder catalysts, which can be used to catalyze the oxygen evolution reaction in water electrolysis.

[0078] 2. This invention provides a novel, simple, low-cost, and low-energy-consumption method for recycling battery materials. It eliminates the need for prolonged high-temperature reactions in pyrometallurgical processes and the large amounts of acid and alkali reagents used in traditional hydrometallurgical processes. Instead, it employs a low-cost, biodegradable citric acid-glucose mixed leaching solvent, reducing environmental pollution from waste liquid.

[0079] 3. The method for preparing composite NiFe-based catalysts provided by this invention directly uses the leachate for in-situ catalyst synthesis, which not only recovers the main transition metal elements in lithium iron phosphate cathodes and high-nickel ternary cathodes, but also simultaneously prepares high-performance composite NiFe catalysts. It eliminates the need for metal element precipitation separation processes and secondary catalyst preparation processes, greatly reducing the recovery process and lowering the recovery cost, and has the potential for large-scale application.

[0080] 4. The method for preparing composite NiFe-based catalysts provided by this invention recovers and reuses transition metal elements in lithium iron phosphate cathodes and high-nickel ternary cathodes, avoiding the energy consumption of repeated mining and saving resources. The catalyst finally prepared exhibits significantly improved catalytic activity compared to commercial catalysts Raney nickel and CN118621359A in alkaline environments, possesses excellent catalytic stability in water electrolysis, and is easy to operate and scale up for production, significantly improving the economic benefits of recycling waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries.

[0081] 5. The method for preparing an anode catalyst for water electrolysis provided by this invention selectively pre-leaches lithium before leaching transition metal elements (such as Ni, Co, Mn, Fe, etc.) from waste cathode materials, enabling the separate recovery and high-value utilization of lithium. Compared to the process of directly co-leaching lithium and other transition metal elements to synthesize catalysts (without separate recovery of lithium), this invention simultaneously achieves the recovery of high-value lithium.

[0082] 6. The self-supported NiFe-based catalyst and NiFe-based powder catalyst prepared by this invention exhibit superior performance compared to the catalyst in CN118621359A. The catalyst prepared by this invention shows better performance at 10 mA / cm². -2The overpotentials at the current densities were 233mV and 243mV, respectively, which were significantly lower than the 277mV at the same current density in CN118621359A. Attached Figure Description

[0083] Figure 1 (a) is a SEM image of nickel foam substrate, and (b) is a SEM image of a self-supporting NiFe-based catalyst (with nickel foam substrate) prepared by simultaneously recovering lithium iron phosphate and high-nickel ternary cathode black powder NCM955.

[0084] Figure 2 (a) Performance comparison of a self-supported NiFe-based catalyst (with nickel foam substrate) prepared by simultaneously recovering lithium iron phosphate and high-nickel ternary NCM 955 cathode black powder with a commercial Raney nickel catalyst; (b) Long-cycle stability performance of the self-supported NiFe-based catalyst for electrocatalytic oxygen evolution reaction.

[0085] Figure 3 SEM image of NiFe-based catalyst powder sample prepared for the recovery of lithium iron phosphate and high-nickel ternary cathode black powder NCM 955;

[0086] Figure 4 A performance comparison chart of Ni-based catalysts prepared for the recovery of high-nickel ternary cathode black powder NCM 955 and NiFe-based catalysts prepared for the simultaneous recovery of lithium iron phosphate and high-nickel ternary cathode black powder NCM 955 (including powder samples and self-supporting substrate samples).

[0087] Figure 5 A comparison of the cyclic voltammetry curves (scan rate 5 mV / s) of the high-nickel ternary cathode black powder after electrochemical selective leaching of lithium as a Ni-based catalyst and the cyclic voltammetry curves (scan rate 5 mV / s) of the powdered NiFe-based catalyst in Example 2.

[0088] Figure 6 A comparison graph showing the cyclic voltammetry curves (scan rate 5 mV / s) of the NiFe-based powder oxide catalyst, the cyclic voltammetry curves (scan rate 5 mV / s) of the sulfided NiFe powder catalyst, and the cyclic voltammetry curves (scan rate 5 mV / s) of the powdered NiFe-based catalyst in Example 2.

[0089] Figure 7 The figure shows the cyclic voltammetry curve (scan rate 5 mV / s) of the powder catalyst generated by post-treatment with NaOH solution. Detailed Implementation

[0090] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0091] A method for preparing a high-performance water electrolysis anode catalyst by recycling cathode materials from waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries includes the following steps: selectively leaching lithium from lithium iron phosphate and high-nickel ternary cathode black powder to obtain a lithium-containing leachate and residual solid powder; adding the residual solid powder to a composite solvent composed of citric acid and glucose to obtain a leachate; mixing the leachate according to a certain nickel-iron molar ratio to obtain a composite leachate; impregnating pretreated foamed nickel in the composite leachate and adding oxalic acid solution dropwise to the composite leachate to obtain a self-supported NiFe-based catalyst intermediate; or directly adding oxalic acid solution dropwise to the composite leachate to obtain a powdered NiFe-based catalyst intermediate; placing the intermediate in KOH solution, then washing and drying to obtain the catalyst.

[0092] The following detailed description is based on specific embodiments.

[0093] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0094] Example 1

[0095] This embodiment provides a method for simultaneously recycling waste lithium iron phosphate and high-nickel ternary cathode powder to prepare high-performance water electrolysis anode catalysts. It illustrates the self-supporting NiFe-based electrocatalyst prepared by the citric acid-glucose mixed leaching agent and seed-assisted growth method provided by this invention. The specific implementation steps are as follows:

[0096] The positive electrode strips of disassembled and completely self-discharged waste lithium iron phosphate batteries and high-nickel ternary NCM955 lithium-ion batteries were cleaned with dimethyl carbonate, then cut into 3cm × 7cm pieces. These were then immersed in 95°C hot water for 10 seconds, manually peeled off, and the positive electrode material was collected. The separated positive electrode material was collected and subjected to heat treatment to remove residual PVDF, yielding waste lithium iron phosphate (LiFePO4) batteries. 0.76 FePO4) and high-nickel ternary cathode black powder NCM955.

[0097] Lithium was selectively leached from the aforementioned waste lithium iron phosphate and high-nickel ternary NCM955 cathode black powder using chemical or electrochemical methods, yielding a lithium-containing leachate and residual solid powder. 2g of Li was added to 10mL of deionized water. 0.76FePO4 and 1.6 g of sodium persulfate were leached at room temperature for 20 min with a stirring speed of 300 rpm. After leaching, the solution containing lithium was obtained by centrifugation at 8000 rpm for 8 min. The black powder was then dried at 80℃ for 12 h to obtain lithium-delithium lithium iron phosphate black powder. 500 mg of high-nickel ternary NCM955 cathode black powder was mixed with 25 mg of PVDF and 500 mg of NMP to prepare a solution. After stirring at 300 rpm for 24 h, the slurry was coated onto graphite paper to a thickness of 200 μm, with an active material loading of 4.5 mg / cm³. 2 The graphite paper was then vacuum-dried at 80℃ for 12 hours. The dried graphite paper was cut into 2cm × 2cm pieces to serve as the positive electrode, and a 1.5cm × 1.5cm platinum sheet was used as the negative electrode. A 0.1M sodium sulfate solution was used as the electrolyte. Electrochemical delithiation was performed under a voltage of 2.25V for 30 minutes with a stirring speed of 200rpm, resulting in a lithium-containing solution. The black powder on the graphite paper was scraped off, ground, and washed with water and ethanol (volume ratio 1:1) to obtain lithium-delithiated high-nickel ternary NCM955 powder.

[0098] Weigh 400 mg of each residual solid powder and dissolve them separately in 20 mL of 1.5 mol / L citric acid solution, then add 200 mg of glucose. The leaching reaction is carried out with continuous stirring at 80 °C for 120 min, yielding two leachates: one containing iron and trace amounts of other transition metals, and the other containing nickel and trace amounts of other transition metals (the atomic ratio of Ni:Co:Mn in the pre-lithium-removed ternary NCM955 leachate is approximately 0.9:0.07:0.02). The two leachates are then uniformly mixed at a volume ratio of 1:0.82 to obtain a composite leachate.

[0099] A 1cm x 2cm piece of nickel foam was cut and ultrasonically cleaned sequentially with 0.5 mol / L hydrochloric acid solution, acetone, and deionized water for 20 min, followed by drying in a vacuum oven. The pretreated nickel foam was then immersed in a mixed leaching solution, and 5 mL of 1.0 mol / L oxalic acid solution was added dropwise while stirring thoroughly to allow the reaction to proceed. After the reaction, the nickel foam was washed several times with ethanol and dried at 60℃ to obtain a self-supported NiFe-based catalyst intermediate. This self-supported NiFe-based catalyst intermediate was then immersed in 1.0 mol / L KOH solution and reacted for 30 min. After drying, a self-supported NiFe-based catalyst was obtained. The scanning electron microscope image of this catalyst is shown below. Figure 1 As shown in b. Figure 1 a is a nickel foam sample. Figure 1 b is a self-supporting NiFe-based catalyst.

[0100] Electrochemical testing: The prepared composite self-supporting NiFe-based catalyst was used as the working electrode, and a counter electrode (platinum sheet) and a HgO / Hg reference electrode were assembled into a three-electrode system. Electrochemical testing of the assembled three-cell system was performed using a Chenhua electrochemical workstation. Stable catalytic performance for the oxygen evolution reaction in water electrolysis was obtained. The self-supporting NiFe-based catalyst prepared in Example 1, compared to commercial Raney nickel catalysts, showed better performance at 10 mA cm⁻¹. -2 The overpotential decreases by approximately 148 mV at current density, and at 50 mA cm⁻¹ -2 The overpotential decreases by approximately 208 mV at current density, such as Figure 2 As shown in Figure a. The self-supported NiFe-based catalyst prepared in Example 1 is subjected to high current density (250 mA cm⁻¹). -2 It can operate stably for over 100 hours, demonstrating excellent cycle stability (e.g., Figure 2 b).

[0101] Example 2

[0102] The composite leachate was obtained according to the experimental steps in Example 1. 5 mL of 1.0 mol / L oxalic acid solution was added dropwise to the composite leachate, and the mixture was stirred thoroughly at room temperature for 1 hour. After the reaction was complete, the mixture was centrifuged, washed, and dried at 60°C to obtain a powdered NiFe-based catalyst intermediate. 50 mg of the powdered NiFe-based catalyst intermediate was weighed, dissolved in 20 mL of 1 M KOH solution, sonicated for 30 minutes, and then centrifuged to separate the precipitate. The precipitate was washed with ethanol, dried at 60°C, and ground to obtain a NiFe-based powdered catalyst. The scanning electron microscope image of this powdered catalyst is shown below. Figure 3 As shown.

[0103] Electrode preparation: The obtained NiFe-based powder catalyst, conductive agent Vulcan Carbon (purchased from Cabot, model XC-72), and binder (Nafion (wt 5%)) were uniformly dispersed in a solvent to obtain a dispersion. The mass ratio of catalyst to conductive agent was 4:1. The dispersion was a mixture of ethanol, water, and Nafion (wt 5%) solutions, with a volume ratio of ethanol, water, and Nafion (wt 5%) of 3:1:0.2. Further, the dispersion was dropwise added to an electrode with an area of ​​0.19625 cm². 2 On a glassy carbon electrode, a catalyst loading of 255 μg cm⁻¹ was obtained. -2 The anode electrode for water electrolysis.

[0104] Electrochemical testing: The prepared glassy carbon working electrode loaded with NiFe-based powder catalyst was assembled into a three-electrode system with a counter electrode (platinum sheet) and a HgO / Hg reference electrode. Electrochemical testing of the assembled three-cell system was performed using a Chenhua electrochemical workstation. For example... Figure 4As shown, the performance of this NiFe-based powder catalyst is very close to that of the self-supporting NiFe-based catalyst in Example 1, both exhibiting superior electrocatalytic oxygen evolution performance compared to commercial Raney nickel catalysts.

[0105] Comparative Example 1

[0106] Following the procedures outlined in Example 1 (after pre-leaching lithium), a leachate of high-nickel ternary NCM955 solid powder with delithiation was obtained. A 1cm x 2cm piece of nickel foam was cut and ultrasonically cleaned sequentially for 20 minutes each with 0.5 mol / L hydrochloric acid, acetone, and deionized water, followed by vacuum drying. The pretreated nickel foam was then immersed in the leachate of the degraded high-nickel ternary powder, and 5 mL of 1.0 mol / L oxalic acid solution was added dropwise while stirring thoroughly to initiate the reaction. After the reaction, the nickel foam was washed several times with ethanol and dried at 60°C to obtain a self-supported Ni-based catalyst intermediate. The self-supported Ni-based catalyst intermediate was then immersed in 1.0 mol / L KOH solution and reacted for 30 minutes, followed by drying to obtain the self-supported Ni-based catalyst.

[0107] After preparing the self-supported Ni-based catalyst intermediate, residual Ni-based powder catalyst intermediate remained in the leachate. The residual Ni-based powder catalyst intermediate was collected and dissolved in 1.0 mol / L KOH solution. After ultrasonic treatment for 30 minutes, the precipitate was separated by centrifugation, washed with ethanol, dried at 60°C, and ground to obtain powdered Ni-based catalyst.

[0108] Electrochemical testing: A three-electrode system was assembled using a glassy carbon electrode (either a composite self-supported Ni-based catalyst or a Ni-based powder catalyst supported on it) as the working electrode, a counter electrode (platinum sheet), and a HgO / Hg reference electrode. The assembled three-electrode system was then electrochemically tested using a Chenhua electrochemical workstation to obtain the catalytic performance of the sample in the water electrolysis oxygen evolution reaction. Figure 4 As shown, the catalytic performance of the self-supporting Ni-based catalyst is better than that of the Ni-based powder catalyst, but neither is as good as the self-supporting NiFe-based catalyst prepared in Example 1 and the NiFe-based powder catalyst prepared in Example 2.

[0109] Comparative Example 2

[0110] Following the procedures outlined in Example 1, lithium was selectively leached from the high-nickel ternary cathode (NCM955, NCM523) black powder using an electrochemical method. The black powder was then scraped off graphite paper, ground, and washed with water and ethanol (volume ratio 1:1) to obtain lithium-free high-nickel ternary powder. After drying and grinding, this solid powder was directly used as a Ni-based catalyst.

[0111] Electrode preparation: The obtained lithium-free high-nickel ternary powder catalyst, conductive agent Vulcan Carbon (purchased from Cabot, model XC-72), and binder (Nafion (wt 5%)) were uniformly dispersed in a solvent to obtain a dispersion. The mass ratio of catalyst to conductive agent was 4:1. The dispersion was a mixture of ethanol, water, and Nafion (wt 5%) solutions, with a volume ratio of ethanol, water, and Nafion (wt 5%) of 3:1:0.2. Further, the dispersion was dropwise added to an area of ​​0.19625 cm². 2 On a glassy carbon electrode, a catalyst loading of 255 μg cm⁻¹ was obtained. -2 The anode electrode for water electrolysis.

[0112] Electrochemical testing: A three-electrode system was assembled using a glassy carbon working electrode loaded with a lithium-free high-nickel ternary powder catalyst, a counter electrode (platinum sheet), and a HgO / Hg reference electrode. The electrolyte was 1M KOH solution. Cyclic voltammetry was performed on the assembled three-cell system using a Chenhua electrochemical workstation, with a voltage range of 1.2–1.7 V vs. RHE and a scan rate of 5 mV / s. The catalytic performance of the sample in the water electrolysis oxygen evolution reaction was obtained, such as... Figure 5 As shown.

[0113] The lithium-free high-nickel ternary NCM955 and NCM523 powder catalyst exhibits a current density of only about 0.56 mA / cm² at 1.55 V (vs. RHE). 2 This is significantly lower than the performance of the NiFe-based catalyst in Example 2 under the same loading and test conditions (current density of 63.23 mA / cm² at 1.55 V (vs. RHE)). 2 ).

[0114] Comparative Example 3

[0115] The composite leachate was obtained following the experimental steps in Example 1. 5 mL of 1.0 mol / L oxalic acid solution was added dropwise to the composite leachate, and the mixture was stirred thoroughly at room temperature for 1 hour. After the reaction was complete, the mixture was centrifuged, washed, and dried at 60°C to obtain a powdered NiFe-based catalyst intermediate. This powdered NiFe-based catalyst intermediate was calcined in a tube furnace at a heating rate of 5°C / min, held at 400°C for 4 hours, cooled to room temperature, and then ground to obtain a NiFe-based powdered oxide catalyst.

[0116] Electrochemical testing: A three-electrode system was assembled using a glassy carbon working electrode (supporting NiFe-based powdered oxide catalyst), a counter electrode (platinum sheet), and a HgO / Hg reference electrode. The electrolyte was 1M KOH solution. Cyclic voltammetry was performed on the assembled three-cell system using a Chenhua electrochemical workstation, with a voltage range of 1.2–1.7 V vs. RHE and a scan rate of 5 mV / s. The catalytic performance of the sample in the water electrolysis oxygen evolution reaction was obtained, such as... Figure 6 As shown.

[0117] The NiFe-based powdered oxide catalyst obtained by this method has a current density of only about 8.72 mA / cm² at 1.55 V (vs. RHE). 2 This is significantly lower than the performance of the NiFe-based catalyst in Example 2 under the same loading and test conditions (current density of 63.23 mA / cm² at 1.55 V (vs. RHE)). 2 ).

[0118] Comparative Example 4

[0119] The NiFe-based powder catalyst was obtained according to the experimental steps in Example 2. 20 mg of the NiFe-based powder catalyst and 5 mg of thioacetamide were dissolved in 20 ml of ethanol for 30 min under stirring to form a uniform suspension. The suspension was then subjected to solvothermal treatment at 160 °C for 8 h. After cooling to room temperature, the suspension was centrifuged, dried, and ground. The resulting sample is referred to as the sulfidated NiFe powder catalyst.

[0120] Electrochemical testing: A three-electrode system was assembled using a glassy carbon working electrode (supporting sulfidated NiFe powder catalyst), a counter electrode (platinum sheet), and a HgO / Hg reference electrode. The electrolyte was 1M KOH solution. Cyclic voltammetry was performed on the assembled three-cell system using a Chenhua electrochemical workstation, with a voltage range of 1.2–1.7 V vs. RHE and a scan rate of 5 mV / s. The catalytic performance of the sample in the water electrolysis oxygen evolution reaction was obtained, such as... Figure 6 As shown.

[0121] The sulfidated NiFe powder catalyst obtained by this method is subjected to 10 mA cm⁻¹ -2 The overpotential at the current density is 270 mV, which is higher than the performance of the NiFe-based catalyst in Example 2 under the same loading and test conditions (10 mA cm⁻¹). -2 The overpotential at the current density is 240mV, indicating that the performance of the sulfidated NiFe powder catalyst is not as good as that of the NiFe-based catalyst in Example 2.

[0122] Comparative Example 5

[0123] The composite leachate was obtained following the experimental steps in Example 1. 5 mL of 1.0 mol / L oxalic acid solution was added dropwise to the composite leachate, and the mixture was stirred thoroughly at room temperature for 1 hour. After the reaction was complete, the mixture was centrifuged, washed, and dried at 60°C to obtain a powdered NiFe-based catalyst intermediate. 50 mg of the powdered NiFe-based catalyst intermediate was weighed, dissolved in 20 mL of 1 M NaOH solution, sonicated for 30 minutes, and then centrifuged to separate the precipitate. The precipitate was washed with ethanol, dried at 60°C, and ground to obtain a powder.

[0124] Electrochemical testing: The prepared glassy carbon working electrode loaded with the above powder was assembled into a three-electrode system with a counter electrode (platinum sheet) and a HgO / Hg reference electrode. The electrolyte was 1M KOH solution. Cyclic voltammetry was used to test the assembled three-cell system using a Chenhua electrochemical workstation, with a voltage range of 1.2–1.7 V vs. RHE and a scan rate of 5 mV / s. The catalytic performance of the sample in the water electrolysis oxygen evolution reaction was obtained, such as... Figure 7 As shown.

[0125] The powdered catalyst obtained by this method has a current density of only about 0.343 mA / cm² at 1.55 V (vs. RHE). 2 This is significantly lower than the performance of the NiFe-based catalyst in Example 2 under the same loading and test conditions (current density of 63.23 mA / cm² at 1.55 V (vs. RHE)). 2 This indicates that the performance of the powder catalyst generated by reacting with NaOH solution is far inferior to that of the NiFe-based powder catalyst in Example 2.

[0126] In summary, this invention provides a method for simultaneously recycling cathode materials from spent lithium iron phosphate (LFP) and ternary lithium-ion (Li-ion) batteries for the preparation of high-performance anode catalysts for water electrolysis. Before leaching transition metal ions (such as iron, nickel, cobalt, and manganese), this method selectively leaches and extracts lithium elements separately, achieving high-value utilization of lithium. Subsequently, a green and low-cost citric acid-glucose mixed leaching solvent is used to leach transition metals from spent LFP and nickel-cobalt-manganese lithium batteries under mild conditions. High-performance self-supporting NiFe-based catalysts and NiFe-based powder catalysts are then prepared in situ using a simple and efficient growth method as electrolyte anode catalysts. This method treats spent LFP and high-nickel ternary cathode materials at a lower cost and achieves efficient recycling and reuse. This unique method not only improves the economic benefits of spent battery recycling but also achieves comprehensive resource utilization and efficient energy conversion, possessing significant economic and environmental implications.

[0127] This invention aims to provide a method for recycling cathode materials from spent lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries to prepare high-performance anode catalysts for water electrolysis. This invention employs a green, low-cost citric acid-glucose mixed leaching solvent to leach transition metals from spent lithium iron phosphate and high-nickel ternary cathode black powder under mild conditions. A simple and efficient method is then used to prepare high-performance composite NiFe-based self-supporting catalysts and NiFe-based powder catalysts. This method processes spent lithium iron phosphate and high-nickel ternary cathode materials at a lower cost and with a shorter process, achieving efficient recycling and reuse.

[0128] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a high-performance anode catalyst for water electrolysis by recycling cathode materials from waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries, characterized in that, Includes the following steps: (1) Discharge the recycled lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries completely, and disassemble and separate the lithium iron phosphate and high-nickel ternary cathode black powder. (2) Selectively leach lithium from the lithium iron phosphate and high-nickel ternary cathode black powder separated in step (1) to obtain lithium-containing leachate and residual solid powder. (3) The residual solid powder recovered in step (2) is added to a composite solvent composed of citric acid and glucose, and the mixture is stirred continuously to carry out the leaching reaction. After the reaction is completed, the leachate is obtained. (4) The leachate obtained in step (3) is uniformly mixed according to a certain nickel-iron molar ratio to obtain a composite leachate; (5) The pretreated nickel foam is immersed in the composite leachate obtained in step (4), and oxalic acid solution is added dropwise to the composite leachate. The mixture is stirred thoroughly at room temperature to carry out the reaction. After the reaction is completed, the nickel foam is washed and dried to obtain a self-supporting NiFe-based catalyst intermediate; or, oxalic acid solution is added dropwise directly to the composite leachate obtained in step (4), and the mixture is stirred thoroughly at room temperature to carry out the reaction. After the reaction is completed, the reaction product is collected, washed and dried to obtain a powdered NiFe-based catalyst intermediate. (6) Place the self-supported NiFe-based catalyst intermediate or powdered NiFe-based catalyst intermediate in KOH solution, then wash and dry to obtain the self-supported NiFe-based catalyst or powdered NiFe-based catalyst.

2. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, The cathode material of the high-nickel ternary lithium-ion battery contains ≥50% nickel by mass.

3. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, Step (2) uses chemical or electrochemical methods to selectively leach lithium from the lithium iron phosphate and high-nickel ternary cathode black powder separated in step (1).

4. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, In step (3), the molar concentration of citric acid in the composite solvent is 1.0 to 3.0 mol / L, the solid-liquid ratio of the residual solid powder to the composite solvent is 5 g:1 L to 50 g:1 L, the mass ratio of the residual solid powder to glucose is 5:1 to 1:1, the leaching temperature is 60 to 90 °C, and the leaching time is 60 to 120 min.

5. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, The nickel-iron molar ratio mentioned in step (4) is 1:1 to 5:

1.

6. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, The solvent for the oxalic acid solution in step (5) is water, ethanol, or a mixture of alcohol and water; the molar ratio of oxalic acid to nickel ions in the composite leachate is 5:1 to 20:1; and the reaction time is 60 to 120 min.

7. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, The pretreatment method for nickel foam described in step (5) includes ultrasonic treatment of nickel foam in HCl solution, organic solvent and deionized water in sequence.

8. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, Step (6) The self-supporting NiFe-based catalyst intermediate is placed in KOH solution for reaction. After the reaction is completed, the reacted nickel foam is washed and dried to obtain the self-supporting NiFe-based catalyst. The molar concentration of the KOH solution is 0.5–5.0 mol / L; the reaction time is 30–60 min; and the drying temperature is 60–120 °C.

9. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, Step (6) The powdered NiFe-based catalyst intermediate is placed in KOH solution, ultrasonically treated, centrifuged to separate the precipitate, washed and dried, and ground to obtain the powdered NiFe-based catalyst; The molar concentration of the KOH solution is 0.5–5.0 mol / L; the ultrasonic treatment time is 30–60 min; and the drying temperature is 60–120 °C.

10. The method for preparing a high-performance water electrolysis anode catalyst using the cathode materials of recycled waste lithium iron phosphate batteries and high-nickel ternary lithium-ion batteries according to claim 1, characterized in that, Step (1) involves separating lithium iron phosphate and high-nickel ternary cathode black powder, including high-temperature sintering, organic solvent cleaning, or hot water bath stripping.

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