Method for stripping and extracting lithium from positive electrode material of waste lithium iron phosphate battery

Abstract

The invention discloses a method for stripping and extracting lithium from a positive electrode material of a waste lithium iron phosphate battery. The method comprises the following steps: (1) disassembling the discharged waste lithium iron phosphate battery to obtain a cathode electrode, cutting the cathode electrode into slices, placing the slices in a quartz boat, and uniformly covering the surfaces of the slices with oxidant powder; the oxidizing agent is selected from one or more of sodium persulfate, ammonium persulfate or potassium persulfate; (2) heating the quartz boat in a muffle furnace, carrying out a roasting reaction in an air atmosphere, and naturally cooling to room temperature after the reaction; and (3) the volume of the roasted sample is fixed with deionized water, heat preservation is performed in a hot water bath, filtrate is a lithium-rich solution, and a filter residue part comprises an aluminum foil and a stripped positive electrode material. According to the method, gas-solid-liquid multiphase synergistic reaction is realized through roasting and leaching processes, and current collector aluminum foil stripping and lithium selective leaching are synchronously realized in a single continuous link.

Description

Technical Field

[0001] This invention relates to the field of waste lithium battery recycling technology, specifically, to a method for stripping and extracting lithium from the cathode material of waste lithium iron phosphate batteries. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the installed capacity of power batteries continues to climb. As the world's largest new energy vehicle market, China's new energy vehicle ownership exceeded 20 million vehicles by 2023, with power battery installations accounting for over 62% of the global total. It is predicted that by 2030, the total amount of retired power batteries in my country will reach approximately 148.7 GWh, with an average annual compound growth rate of 37.64% between 2025 and 2030. How to achieve efficient resource utilization of retired batteries has become a key technological bottleneck restricting the sustainable development of the battery industry.

[0003] Waste lithium-ion battery cathode materials are rich in high-value metal resources such as lithium (3.5-5 wt%), cobalt, and nickel. Lithium recovery, in particular, is crucial for ensuring resource supply and supporting the development of energy storage technologies. However, current mainstream wet recycling processes typically employ a step-by-step approach of "separating the current collector first, then extracting lithium." This process is not only cumbersome and inefficient but also consumes a large amount of acid. During recycling, the aluminum foil in the current collector is corroded by strong acid, leading to aluminum waste and lithium-aluminum co-precipitation, resulting in irreversible lithium loss. Pyrometallurgical processes also suffer from problems such as high-temperature lithium volatilization, resulting in low overall lithium leaching rates and a heavy environmental burden, making it difficult to meet the demands for green and efficient recycling. Summary of the Invention

[0004] This invention aims to solve the technical problems of traditional recycling processes for waste lithium iron phosphate batteries, which are characterized by "low efficiency, high cost, high acid consumption, and high lithium loss due to step-by-step processing." It provides a method for stripping and extracting lithium from the cathode material of waste lithium iron phosphate batteries. This method is economical, green, and efficient, and can achieve efficient stripping of the cathode electrode and simultaneous extraction of lithium resources.

[0005] The technical solution of the present invention is described in detail below.

[0006] A method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries includes the following steps: (1) Disassemble the waste lithium iron phosphate battery after discharge to obtain the cathode electrode. The positive electrode material and the current collector aluminum foil in the cathode electrode are in an unseparated state. Cut the cathode electrode into thin sheets and place them in a quartz boat. Cover the cathode electrode surface with oxidant powder evenly. The oxidant is selected from one or more of sodium persulfate, ammonium persulfate or potassium persulfate. The mass ratio of oxidant powder to cathode electrode is 0.5:1-3:1. (2) The quartz boat is heated in a muffle furnace and calcined in an air atmosphere; after the reaction is completed, the quartz boat is taken out of the furnace and cooled naturally to room temperature; the calcination temperature is 350℃-550℃ and the calcination time is 10-90min. (3) The calcined cathode material was diluted with deionized water and kept warm in a water bath for a certain time. Finally, it was filtered to obtain filtrate and filter residue. The filtrate was a lithium-rich solution. (4) Dry the filter residue, then collect the cathode electrode and sieve it to separate the positive electrode material and the current collector aluminum foil. Weigh the stripped positive electrode material to determine the separation efficiency.

[0007] Preferably, in step (1), the cathode electrode is cut into a thin sheet of 1cm×1cm-5cm×5cm; more preferably, the cathode electrode is cut into a thin sheet of 1cm×1cm-2cm×2cm.

[0008] Preferably, in step (1), the mass ratio of oxidant powder to cathode electrode is 1.5:1 to 2.5:1. More preferably, the mass ratio of oxidant powder to cathode electrode is 1.5:1 to 2.0:1. In a specific embodiment, sodium persulfate is used as the oxidant. Lithium iron phosphate material is relatively stable. When the oxidant content is too low, the oxygen generated under calcination conditions is insufficient to oxidize the lithium iron phosphate cathode material, and lithium cannot be extracted from the stable structure, affecting lithium leaching. Excessive oxidant will cause corrosion or over-oxidation of the lithium iron phosphate surface, thereby affecting the stripping rate of the cathode material.

[0009] Preferably, in step (2), the calcination temperature is 420-480℃ and the calcination time is 15-60min. According to thermogravimetric analysis, if the calcination temperature is too low, the oxidant is not thermally decomposed enough and is not sufficient to provide enough oxygen for the reaction; if the calcination time is too long, the O2 released by the thermal decomposition of the oxidant is completely consumed, resulting in a small amount of lithium not being converted into soluble lithium salt.

[0010] Preferably, in step (2), when the quartz boat is heated in the muffle furnace, the heating rate is 3-6℃ / min.

[0011] Preferably, in step (3), lithium extraction is performed by water immersion. The calcined cathode material is diluted with deionized water at a mass-to-volume ratio of 1:10-1:50 g / mL, and then kept at a water bath temperature of 20℃-70℃ for 5-60 min. More preferably, the water bath temperature is 50-60℃ and the holding time is 20-30 min.

[0012] Preferably, in step (3), the filtrate is selectively reused, including: adjusting the pH of the leachate to remove impurities, heating the leachate to 85-95°C, adding a prepared saturated sodium carbonate solution, heating and evaporating to concentrate and promote lithium carbonate crystallization, and then filtering and washing with hot water to obtain the lithium carbonate product. The filter residue is flaky and is a mixture of positive electrode material and aluminum foil. The filter residue is the separated cathode electrode. After leaching and filtration, the positive electrode material and aluminum foil in the cathode electrode have been separated.

[0013] Preferably, in step (4), the filter residue is dried in an oven at a temperature of 50-80°C.

[0014] This invention introduces a sulfidation control mechanism at a lower temperature. By breaking the C–F bonds in PVDF, the interfacial behavior between materials is precisely controlled, avoiding lithium volatilization and aluminum fusion problems caused by traditional high-temperature calcination. Simultaneously, a "calcination-water leaching synchronous coupling system" is constructed to achieve gas-solid-liquid multiphase synergistic reaction, matching the kinetic rates of the sulfidation process and the lithium dissolution process, improving lithium recovery efficiency, reducing acid consumption, and simplifying the processing flow. Current collector stripping and selective lithium leaching are achieved simultaneously. Compared with existing technologies, this invention has the following beneficial effects: (1) This invention enables the simultaneous stripping of the cathode material and the aluminum foil current collector and the extraction of lithium, thereby improving processing efficiency; (2) This invention does not use strong acid or strong alkali solutions, which greatly reduces acid consumption and environmental burden; (3) This invention significantly improves the metal recovery rate (aluminum, lithium) and reduces resource loss. Attached Figure Description

[0015] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the invention.

[0017] Example 1

[0018] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 0.5:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 50.18%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 94.22%.

[0019] Example 2

[0020] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 1:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 65.14%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 93.75%.

[0021] Example 3

[0022] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 1.5:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 93.31%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 93.75%.

[0023] Example 4

[0024] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 100%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 95.05%.

[0025] Example 5

[0026] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 3:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 95.95%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 83.88%.

[0027] Example 6

[0028] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 350°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 350°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a water bath at 60°C for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 91.55%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 62.5%.

[0029] Example 7

[0030] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 500°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 500°C for 15 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 88.46%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 92.43%.

[0031] Example 8

[0032] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 550°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 550°C for 45 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 93.31%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 66.6%.

[0033] Example 9

[0034] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, the quartz boat was calcined in an air atmosphere at 450°C for 15 minutes at a heating rate of 5°C / min. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 90.67%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 94.88%.

[0035] Example 10

[0036] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, the quartz boat was calcined in an air atmosphere at 450°C for 30 minutes at a heating rate of 5°C / min. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 93.22%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the positive electrode material and the current collector aluminum foil. The peeling rate was 94.44%.

[0037] Example 11

[0038] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 60 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a water bath at 60°C for 15 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 95.07%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the positive electrode material and the current collector aluminum foil. The peeling rate was 92.36%.

[0039] Example 12

[0040] This embodiment provides a method for stripping and extracting lithium from the cathode material of spent lithium iron phosphate batteries, including the following steps: (1) After the waste lithium iron phosphate battery is processed by discharge, dismantling and other processes, the cathode electrode is obtained. It is cut into a 2cm×1cm thin sheet, placed in a quartz boat, and covered with oxidant (sodium persulfate) powder evenly. The mass ratio of oxidant powder to cathode electrode is 2:1. (2) Subsequently, under an air atmosphere, the temperature was increased to 450°C in a muffle furnace at a heating rate of 5°C / min, and then calcined at 450°C for 75 minutes. After the calcination reaction was completed, the quartz boat was removed from the furnace and slowly cooled to room temperature; (3) The calcined cathode electrode was added to a measured amount of deionized water and soaked in a 60°C water bath for 30 minutes to achieve selective leaching of lithium. After water leaching, solid-liquid separation was performed, and the leaching rate of Li in the filtrate was measured to be 95.95%. (4) The filter residue was dried in an oven at 60°C. Then the cathode electrode was collected and sieved to separate the cathode material and the current collector aluminum foil. The peeling rate was 93.61%.

[0041] The results of Examples 1 to 12 are shown in Table 1: Table 1

[0042] The foregoing has shown and described the main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. A method for stripping and extracting lithium from the cathode material of waste lithium iron phosphate batteries, characterized in that, Includes the following steps: (1) Disassemble the waste lithium iron phosphate battery after discharge to obtain the cathode electrode. The positive electrode material and the current collector aluminum foil in the cathode electrode are in an unseparated state. Cut the cathode electrode into thin sheets and place them in a quartz boat. Cover the cathode electrode surface with oxidant powder evenly. The oxidant is selected from one or more of sodium persulfate, ammonium persulfate or potassium persulfate. The mass ratio of oxidant powder to cathode electrode is 0.5:1-3:

1. (2) The quartz boat is heated in a muffle furnace and calcined in an air atmosphere; after the reaction is completed, the quartz boat is taken out of the furnace and cooled naturally to room temperature; the calcination temperature is 350℃-550℃ and the calcination time is 10-90min. (3) The calcined cathode material was diluted with deionized water and kept warm in a water bath for a certain time. Finally, it was filtered to obtain filtrate and filter residue. The filtrate was a lithium-rich solution. (4) Dry the filter residue, then collect the cathode electrode and sieve it to separate the positive electrode material and the current collector aluminum foil. Weigh the stripped positive electrode material to determine the separation efficiency.

2. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode material according to claim 1, characterized in that, In step (1), the cathode electrode is cut into thin sheets of 1cm×1cm-5cm×5cm.

3. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode materials according to claim 1, characterized in that, In step (1), the mass ratio of oxidant powder to cathode electrode is 1.5:1 to 2.5:

1.

4. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode material according to claim 1, characterized in that, In step (2), the roasting temperature is 350-550℃ and the roasting time is 15-60min.

5. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode material according to claim 1, characterized in that, In step (2), when the quartz boat is heated in the muffle furnace, the heating rate is 5-10℃ / min.

6. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode material according to claim 1, characterized in that, In step (3), the calcined cathode material is diluted with deionized water at a mass-to-volume ratio of 1:10-1:50 g / mL, and then kept warm in a water bath at 20℃-70℃ for 5-60 min.

7. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode material according to claim 1, characterized in that, In step (3), the filtrate is selectively reused in the following steps: adjusting the pH of the leachate to remove impurities, heating the leachate to 85-95°C, adding the prepared saturated sodium carbonate solution, heating and evaporating to concentrate and promote the crystallization of lithium carbonate, and then filtering and washing with hot water to obtain the lithium carbonate product.

8. The method for stripping and extracting lithium from waste lithium iron phosphate battery cathode material according to claim 1, characterized in that, In step (4), the filter residue is dried in an oven at a temperature of 50-80℃.

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