CN109119711B - A method for preparing high-voltage positive electrode material by using waste lithium cobalt oxide battery - Google Patents

Abstract

The invention discloses a method for preparing a high-voltage positive electrode material by using waste and used lithium cobalt oxide batteries. The stripped waste and used and used lithium cobalt oxide battery positive electrode materials are cleaned and calcined, and the content of cobalt and lithium therein is detected; Take nickel salt, cobalt salt and manganese salt in stoichiometric ratio, prepare a mixed salt solution of nickel salt, cobalt salt and manganese salt, and then prepare complexing agent solution I, complexing agent solution II and precipitant solution respectively; Add the complexing agent solution II as the bottom liquid and add the calcined waste lithium cobaltate material, and add the nickel-cobalt-manganese mixed salt solution, the complexing agent solution I, and the precipitating agent solution separately to carry out the precipitation reaction, and control the pH value, The concentration of the complexing agent, the reaction temperature, the reaction time, filtration, cleaning and drying to obtain a composite precursor, the composite precursor is mixed with a lithium source and calcined and then cooled to room temperature to obtain a positive electrode material; the material prepared by the present invention has high crystallinity, High structural stability and good high-voltage charge-discharge cycle stability.

Description

A method for preparing high-voltage positive electrode material by using waste lithium cobalt oxide battery

technical field

The invention relates to the field of recycling and reuse of waste lithium ion batteries, in particular to a method for preparing high-voltage positive electrode materials by using waste lithium cobalt oxide batteries.

Background technique

Lithium-ion batteries are recognized by the international community as the most ideal chemical power source for their high energy density, long life, small self-discharge, no memory effect and green environmental protection. They are widely used in mobile phones, notebook computers, power tools and portable cameras. and other electronic products. At the same time, lithium-ion batteries play an important role in intermittent clean energy storage fields such as wind, solar and tidal energy. In addition, the expanding fields of electric vehicles, electric bicycles, aerospace, military mobile communication tools and equipment will bring more development space for lithium-ion batteries. However, after the lithium-ion battery is charged and discharged for many times, the active material is inactivated and scrapped due to structural changes. Therefore, the number of waste lithium-ion batteries is huge. The release of electrolyte in waste lithium-ion batteries will pollute the environment and harm the ecosystem. At the same time, the electrode materials contain a large amount of valuable metals such as nickel, iron, manganese, cobalt, and lithium. The rapid development of the new energy industry has led to the development of lithium-ion battery raw materials. Mineral resources are decreasing day by day, restricting the healthy development of the lithium-ion battery industry. Therefore, scientific and efficient recycling of waste lithium-ion batteries has become an urgent problem to be solved.

So far, lithium cobalt oxide is an irreplaceable cathode material for lithium-ion batteries in the field of mid-to-high-end electronics, and with the long-term charge-discharge cycle, the number of scrapped lithium cobalt oxide batteries is increasing day by day. Up to now, the recycling methods of waste lithium cobalt oxide batteries mainly focus on the wet process and the fire process, and mainly focus on the recovery of valuable metal elements. Among them, the fire method has high energy consumption, serious pollution and poor separation effect; while the wet method has the advantages of mild conditions and low energy consumption, but the wet method cannot avoid the discharge of a large number of three wastes, and the process flow is long and the technical requirements are high. Process control is difficult and a series of problems. The active material in the cathode material of the waste battery basically retains the composition and structure of the active material before the failure. Directly processing the cathode material of the waste battery to prepare a new cathode material for recycling will greatly shorten the technical process and cycle of battery recycling. At present, many teams have developed a series of scientific recycling methods for waste lithium cobalt oxide. CN 103199319A discloses a method for recovering lithium cobalt oxide from waste positive electrode sheets of lithium cobalt oxide batteries, and CN 102703706B soaks and strips the active material of the battery through an organic solvent, which can dissolve most of the binder and directly obtain clean aluminum , copper, nickel foil and diaphragm, and promote the direct contact reaction between the subsequent acid solution and lithium cobaltate, and use sulfuric acid solution to dissolve LiCoO ₂ . However, the above methods have the following deficiencies: 1) the treatment of the positive electrode material after stripping still involves wet leaching and precipitation processes, the process flow is relatively long, and the technical difficulty is relatively large; 2) the recovered materials cannot be directly used as active materials, Product value added is not obvious. Invention patent CA105428747A discloses a method for recovering lithium cobalt oxide in waste batteries by treating with lithium hydroxide solution. However, the performance of the repair material obtained by this method is only the level of ordinary lithium cobalt oxide material, and the value-added is not obvious. Lithium-rich manganese-based solid solution has become a very popular series of materials due to its low cost, low toxicity, high energy density, and high voltage. In 2001, Zhonghua Lu et al. successfully developed Li-rich manganese-based solid solution for the first time. The molecular formula of this material can be expressed as xLi ₂ MO ₃ •(1-x)LiM'O ₂ (M is Mn, Ti, Zr, etc., or any combination thereof. ; M' is Mn, Ni or Co, 0≤x≤1), which can be regarded as the layered compound Li ₂ MnO ₃ (ie Li[Li _1/3 Mn _2/3 ]O ₂ ) and LiM'O ₂ . These manganese-rich bicomponent materials not only have high capacity, wide charge _- discharge voltage window, low cost, environmental friendliness, and good safety, but also have a capacity approximately twice that of LiCoO2, which has attracted extensive attention from researchers. Yu LY et al. synthesized 0.65Li[Li _1/3 Mn _2/3 ]O ₂ •0.35Li[Ni _1/3 Co _1/3 Mn _1/3 ]O ₂ at 700 ℃ by high-temperature solid-phase method, The initial capacity is only 97mAh/g (2.5-4.6V, 100mAh/g), and the capacity obtained after several activations is 229mAh/g. By reviewing the current patent literature on recycling technology, there is no literature report on the direct preparation of high-voltage lithium cobalt oxide materials from waste lithium cobalt oxide batteries as cathode materials for lithium ion batteries.

SUMMARY OF THE INVENTION

In view of the problems and deficiencies in the prior art, the present invention provides a method for preparing high-voltage positive electrode materials by using waste and used lithium cobalt oxide batteries, which can simply and efficiently recycle waste and used lithium cobalt oxide batteries, and prepare high-performance high-voltage positive electrode materials. , to achieve effective recycling and reuse of waste lithium cobalt oxide batteries.

A method for preparing a high-voltage positive electrode material by using waste and used lithium cobalt oxide batteries, specifically comprising the following steps:

(1) Take the waste lithium cobalt oxide battery cathode material obtained by stripping, clean it, and then place it in a muffle furnace for calcination to remove impurities such as conductive carbon and binder to obtain waste lithium cobalt oxide powder material, and detect the content of cobalt and lithium in it. ;

(2) According to the stoichiometric ratio of the lithium-rich manganese-based solid solution (xLi[Li _1/3 Mn _2/3 ]O ₂ ·(1–x)LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), it is called Take the corresponding nickel salt, cobalt salt and manganese salt, prepare a mixed salt solution of nickel salt, cobalt salt and manganese salt, the sum of the concentrations of Ni+Co+Mn in the mixed salt solution is 0.01~2mol/L, and then prepare separately Complexing agent solution I with concentration of 1~14mol/L, complexing agent solution II with concentration of 0.1~0.5mol/L and precipitant solution with concentration of 0.5~10mol/L, complexing agent solution I and complexing agent solution The complexing agent in II is the same;

(3) Add complexing agent solution II as the bottom liquid and add the waste lithium cobalt oxide material obtained by calcination in step (1), and mix the nickel-cobalt-manganese mixed salt solution of step (2), complexing agent solution I, The precipitant solution was added to the reaction kettle by flow respectively, and the nickel-cobalt-manganese salt mixed solution was calculated according to the waste lithium cobalt oxide material and the theoretical lithium-rich manganese-based solid solution (xLi[Li _1/3 Mn _2/3 ]O ₂ ·(1-x)LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) was added in a mass ratio of 100:0.1~10, and the flow of each solution was controlled during the reaction. The pH value of the liquid in the reaction kettle is controlled by the acceleration to be 9~11, the concentration of the complexing agent is controlled to be 0.1~0.5mol/L, the reaction temperature is 20~95°C, and the reaction is performed for 10~260min to obtain a slurry containing the precursor material. The material is filtered, washed and dried to obtain a composite precursor;

(4) The composite precursor obtained in step (3) and the lithium source are uniformly mixed in a ratio of (Ni+Co+Mn):Li molar ratio of 1:1~1.1 in the final product, and placed in an atmosphere furnace for 600 ℃ in an air atmosphere. calcined at ~950 °C for 2~20 h, and then cooled to room temperature to obtain a positive electrode material.

In step (2), x is 0.1 to 0.9.

The nickel salt in step (2) is one or more of nickel sulfate, nickel chloride, nickel acetate or nickel nitrate.

The cobalt salt in step (2) is one or more of cobalt sulfate, cobalt chloride, cobalt acetate or cobalt nitrate.

The manganese salt in step (2) is one or more of manganese sulfate, manganese chloride, manganese acetate or manganese nitrate.

In step (2), the complexing agent is one or more of ammonia water, triethanolamine, citric acid, oxalic acid, sodium EDTA and ammonium bicarbonate mixed in any proportion.

In step (2), the precipitating agent is sodium hydroxide, and the precipitating agent is also used as a pH value control agent.

In step (3), the washing is to use deionized water at 20-80°C to wash the precipitate several times until the pH value of the final washing solution is lower than 10; and the drying is drying at 60-150°C for 6-60 hours.

The lithium source in step (4) is lithium hydroxide or lithium carbonate.

The present invention proposes to introduce Li-rich manganese-based solid solution (xLi[Li _1/3 Mn _2/3 ]O ₂ ·(1-x)LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) into spent cobalt acid for the first time On the lithium surface modification, a high-voltage lithium cobalt oxide-based composite cathode material with high voltage stability can be prepared, which can realize efficient and green recycling and reuse of waste lithium cobalt oxide batteries; the material prepared by the present invention has high crystallinity and structural stability. High, high-voltage charge-discharge cycle stability is good; the invention avoids the leaching and recycling process, and can directly convert waste lithium cobalt oxide battery cathode materials into high-performance high-voltage lithium cobalt oxide cathode materials, so as to realize the efficient green of waste lithium cobalt oxide. Repair and value-added utilization, the method is simple, efficient and highly implementable.

Description of drawings

Fig. 1 is the process flow diagram of embodiment 1 of the present invention;

Figure 2 is a SEM comparison of the lithium cobalt oxide obtained by exfoliation in step (1) and the composite precursor obtained in step (3) in Example 1 of the present invention (Fig. a is the lithium cobalt oxide obtained by exfoliation, Fig. b is obtained in step (3) composite precursor);

Fig. 3 is the XRD pattern of the positive electrode material prepared in Example 1 of the present invention;

4 is a TEM image of the positive electrode material prepared in Example 2 of the present invention;

5 is a 1C cycle performance curve of the positive electrode material prepared in Example 2 of the present invention;

FIG. 6 is a SEM comparison diagram of the lithium cobalt oxide obtained by exfoliation in step (1) of Example 3 of the present invention and the positive electrode material (the lithium cobalt oxide obtained by exfoliation in Figure a, and the positive electrode material obtained in Figure b).

Detailed ways

The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

Example 1

A method for preparing high-voltage positive electrode material using waste and old cobalt oxide batteries, as shown in Figure 1, specifically comprises the following steps:

(1) The waste lithium cobalt oxide battery is placed in a 2mol/L sodium sulfate solution to release the residual electricity, and the discharge time is 24h. The positive electrode sheet is separated, and it is placed in a sodium hydroxide solution with a concentration of 6% by mass, stirring The reaction was carried out for 12 hours, and the filter residue was washed and filtered to obtain waste cathode material; the obtained filter residue was calcined in an atmosphere furnace at 600 °C for 2 hours to obtain waste LiCoO ₂ powder material, and the percentage content of cobalt and lithium (Co, Li) was detected;

(2) According to the stoichiometric ratio of lithium-rich manganese-based solid solution (0.9Li[Li _1/3 Mn _2/3 ]O ₂ ·0.1LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), weigh nickel sulfate , cobalt sulfate and manganese sulfate, prepared into a mixed salt solution of nickel salt, cobalt salt and manganese salt, the sum of the concentrations of Ni+Co+Mn in the mixed salt solution is 0.01mol/L, and the concentration is 1mol/L lemon respectively. Acid solution, 0.1mol/L citric acid solution and 5mol/L sodium hydroxide solution;

(3) 1L of 0.1mol/L citric acid solution was added to the reaction kettle as the bottom liquid, and 100g of waste lithium cobalt oxide material obtained by calcination in step (1) was added, and the nickel-cobalt-manganese mixed salt solution of step (2), 1mol /L citric acid solution and sodium hydroxide solution were added to the reaction kettle for precipitation reaction respectively, and the feeding rate of nickel-cobalt-manganese mixed salt solution was 10 mL/min, wherein the nickel-cobalt-manganese mixed salt solution was based on the quality and The mass ratio of the lithium-rich manganese-based solid solution (0.9Li[Li _1/3 Mn _2/3 ]O ₂ ·0.1LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) calculated from the theoretical calculation of the nickel-cobalt-manganese mixed salt is The ratio of 100:0.1 was added, and the pH value during the reaction was controlled to 9±0.1 by controlling the flow rates of 1 mol/L citric acid solution and sodium hydroxide solution, and the concentration of the complexing agent citric acid was controlled to be 0.1 mol/L , the reaction temperature was 20 °C, and the reaction was carried out for 10 min to obtain a slurry containing the precursor material. The precursor material was filtered, and the precipitate was washed with deionized water at 20 °C for several times until the final pH value was lower than 10, and then dried at 60 °C for 60 h to obtain composite precursor;

(4) The content of Ni, Co, Mn and Li is analyzed on the composite precursor obtained in step (3), and lithium hydroxide is added according to the molar ratio (Ni+Co+Mn):Li=1:1, After mixing uniformly, it was calcined at 950 °C for 2 h in an air atmosphere, and then cooled to room temperature to obtain a positive electrode material. The analysis results showed that the coating phase in the composite material was 0.9Li[Li _1/3 Mn _2/3 ]O ₂ ·0.1 The mass percentage of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ is 0.1%, and the mass percentage of the main phase LiCoO ₂ is 99.9%.

Fig. 2 is a SEM comparison diagram of the lithium cobalt oxide obtained by peeling off in step (1) and the composite precursor obtained by step (3) in Example 1 of the present invention (Fig. a is the lithium cobalt oxide obtained by peeling off, Fig. b is obtained in step (3)) It can be seen from the figure that a uniformly coated composite precursor can be obtained after step (3); Figure 3 is the XRD pattern of the finally obtained positive electrode material, it can be seen from the figure that the crystallinity of the positive electrode material is higher than that of waste cobalt The lithium oxide material is significantly enhanced, and the crystal structure is effectively repaired; the coin-type battery prepared by using this positive electrode material as the positive electrode is subjected to constant current charge and discharge tests within the voltage window of 3.0~4.5V, and the first discharge capacity at 0.1C is 191mAh/ g, as shown in Fig. 5, the discharge specific capacity remains at 186mAh/g at 1C, and the capacity retention rate is 87.6% after 100 cycles.

Example 2

A method for preparing high-voltage positive electrode material using waste and old cobalt oxide battery, specifically comprising the following steps:

(1) The waste lithium cobalt oxide battery is placed in a 2mol/L sodium sulfate solution to release the residual electricity, and the discharge time is 24h. The positive electrode sheet is separated, and it is placed in a sodium hydroxide solution with a concentration of 6% by mass, stirring The reaction was carried out for 12 hours, and the filter residue was washed and filtered to obtain waste cathode material; the obtained filter residue was calcined in an atmosphere furnace at 600 °C for 2 hours to obtain waste LiCoO ₂ powder material, and the percentage content of cobalt and lithium (Co, Li) was detected;

(2) According to the stoichiometric ratio of the lithium-rich manganese-based solid solution (0.6Li[Li _1/3 Mn _2/3 ]O ₂ ·0.4LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), weigh the chloride Nickel, cobalt chloride and manganese chloride are prepared into mixed salt solutions of nickel salts, cobalt salts and manganese salts. The sum of the concentrations of Ni+Co+Mn in the mixed salt solution is 1 mol/L, and the concentration is 5 mol/L respectively. L triethanolamine aqueous solution, 0.3mol/L triethanolamine aqueous solution and 0.5mol/L precipitant sodium hydroxide solution;

(3) Add 10 L of 0.3 mol/L triethanolamine aqueous solution as bottom liquid and add 5000 g of waste lithium cobalt oxide material obtained by calcination in step (1) into the reaction kettle, mix the nickel-cobalt-manganese mixed salt solution of step (2), The triethanolamine aqueous solution and sodium hydroxide solution of 5mol/L were added to the reaction kettle for precipitation reaction respectively, and the feeding rate of the nickel-cobalt-manganese mixed salt solution was 20 mL/min. The mass ratio of Li-rich manganese-based solid solution (0.6Li[Li _1/3 Mn _2/3 ]O ₂ ·0.4LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) calculated theoretically with Ni-Co-Mn mixed salt Add for the ratio of 100:5, control the pH value in the reaction process to be 10 ± 0.1 by controlling the flow rate of the triethanolamine aqueous solution and sodium hydroxide solution of 5mol/L, and control the concentration of the complexing agent triethanolamine to be 0.3mol/ L, the reaction temperature was 60 °C, and the reaction was performed for 115 min to obtain a slurry containing the precursor material. The precursor material was filtered, and the precipitate was washed with deionized water at 50 °C for several times until the final pH value was lower than 10. Dry at 80 °C for 50 h to obtain a composite precursor;

(4) The content of Ni, Co, Mn and Li is analyzed on the composite precursor obtained in step (3), and lithium hydroxide is added according to the molar ratio (Ni+Co+Mn):Li=1:1.08, After mixing uniformly, it was calcined at 850 °C for 10 h in an air atmosphere, and then cooled to room temperature to obtain a positive electrode material. The analysis results showed that the coating phase in the composite material was 0.6Li[Li _{1/ 3} Mn _2/3 ]O ₂ ·0.4 The mass percentage of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ is 5%, and the mass percentage of the main phase LiCoO ₂ is 95%.

Figure 4 shows the transmission electron microscopy (TEM) results of the positive electrode material obtained in this example. From the TEM data, it can be clearly seen that the surface of the substrate LiCoO ₂ is covered with a uniform Li-rich manganese-based solid solution phase; The discharge capacity is 189mAh/g, as shown in Figure 5, the discharge specific capacity is maintained at 182mAh/g at 1C, and the capacity retention rate is 94.5% after 100 cycles.

Example 3

A method for preparing high-voltage positive electrode material using waste and old cobalt oxide battery, specifically comprising the following steps:

(1) The waste lithium cobalt oxide battery is placed in a 2mol/L sodium sulfate solution to release the residual electricity, and the discharge time is 24h. The positive electrode sheet is separated, and it is placed in a sodium hydroxide solution with a concentration of 6% by mass, stirring The reaction was carried out for 12 hours, and the filter residue was washed and filtered to obtain waste cathode material; the obtained filter residue was calcined in an atmosphere furnace at 600 °C for 2 hours to obtain waste LiCoO ₂ powder material, and the percentage content of cobalt and lithium (Co, Li) was detected;

(2) According to the stoichiometric ratio of the lithium-rich manganese-based solid solution (0.1Li[Li _1/3 Mn _2/3 ]O ₂ ·0.9LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), weigh the nickel nitrate , cobalt nitrate and manganese nitrate, prepared into a mixed salt solution of nickel salt, cobalt salt and manganese salt, the sum of the concentrations of Ni+Co+Mn in the mixed salt solution is 2mol/L, and then the ammonia concentration of 14mol/L is prepared separately. Aqueous solution, 0.5mol/L ammonia solution and 10mol/L precipitant sodium hydroxide solution;

(3) 10L of 0.5mol/L ammonia solution was added to the reaction kettle as the bottom liquid and 5000g of waste lithium cobalt oxide material obtained by calcination in step (1) was added, and the nickel-cobalt-manganese mixed salt solution of step (2), 14mol/L L of ammonia solution and sodium hydroxide solution were added to the reaction kettle for precipitation reaction respectively, and the feeding rate of nickel-cobalt-manganese mixed salt solution was 10mL/min, wherein the nickel-cobalt-manganese salt mixed solution was based on the quality of waste lithium cobalt oxide powder and nickel-cobalt The mass ratio of the lithium-rich manganese-based solid solution (0.1Li[Li _1/3 Mn _2/3 ]O ₂ ·0.9LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) calculated from the theoretical calculation of the manganese mixed salt is 100: The ratio of 10 was added, and the pH value during the reaction was controlled to be 11±0.1 by controlling the flow rate of 14mol/L ammonia solution and sodium hydroxide solution, and the concentration of the complexing agent ammonia (NH ₃ ) was controlled to be 0.5mol/L , the reaction temperature was 95 °C, and the reaction was carried out for 260 min to obtain a slurry containing the precursor material. The precursor material was filtered, and the precipitate was washed with deionized water at 80 °C for several times until the final pH value was lower than 10, and then dried at 150 °C for 6h to obtain composite precursor;

(4) The content of Ni, Co, Mn and Li is analyzed on the composite precursor obtained in step (3), and lithium carbonate is added according to the molar ratio (Ni+Co+Mn):Li=1:1.1, and mixed. After being uniformly placed in an air atmosphere and calcined at 600 °C for 20 hours, then cooled to room temperature to obtain a positive electrode material. The analysis results show that the coating phase in the composite material is 0.9Li[Li _1/3 Mn _2/3 ]O ₂ ·0.1LiNi The mass ratio of _1/3 Co _1/3 Mn _1/3 O ₂ is 10%, and the mass percentage of the main phase LiCoO ₂ is 90%.

Figure 6 is a SEM comparison diagram of the lithium cobalt oxide obtained by peeling off in step (1) in Example 3 of the present invention and the positive electrode material (the lithium cobalt oxide obtained by peeling off in Figure a, and the positive electrode material obtained in Figure b in step (3)), from the SEM image It can be seen that the morphology of the exfoliated lithium cobalt oxide and the cathode material, that is, before and after modification, are all monodisperse particle morphology, and there is no single small particle between the particles of the composite material obtained after coating, indicating that the coating source is all distributed. On the surface of LiCoO ₂ particles, a uniform coating layer was formed; the coin-cell battery prepared by using this cathode material as the cathode was tested by constant current charge-discharge cycle within the voltage window of 3.0~4.5V, and the composite material was the first at 0.1C. The discharge capacity is 195mAh/g, the discharge specific capacity remains at 188mAh/g at 1C, and the capacity retention rate is 89.9% after 100 cycles.

Table 1 below shows the waste LiCoO ₂ material recovered in step (1) and the materials obtained in Examples 1, 2, and 3 as positive electrodes to prepare lithium ion button batteries and perform constant current charge-discharge cycle tests within the 3.0-4.5V voltage window. , it can be seen from the figure that the electrochemical properties of the cathode materials prepared in Examples 1, 2, and 3 have been significantly improved compared with the waste LiCoO ₂ materials.

Table 1 Electrochemical properties (voltage range 3.0~4.5V)

It should be noted that the above-described embodiments illustrate rather than limit the invention, and that various alternative embodiments may be devised by those skilled in the art without departing from the scope of the appended claims. It should be understood that any improvement of the present invention, equivalent replacement of the selected components of the present invention, addition of auxiliary components, selection of specific modes, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims (9)

1. a method that adopts waste and old cobalt oxide lithium battery to prepare high-voltage positive electrode material, is characterized in that, specifically comprises the following steps: (1) Washing and calcining the waste lithium cobalt oxide battery cathode material obtained by stripping to obtain waste lithium cobalt oxide material, and detecting the content of cobalt and lithium therein; (2) According to the stoichiometric ratio of Li-rich manganese-based solid solution xLi[Li _1/3 Mn _2/3 ]O ₂ ·(1–x)LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , weigh out the nickel Salt, cobalt salt and manganese salt are prepared into a mixed salt solution of nickel salt, cobalt salt and manganese salt. The sum of the concentrations of Ni+Co+Mn in the mixed salt solution is 0.01~2mol/L, and the concentration is 1~2mol/L. 14mol/L complexing agent solution I, complexing agent solution II with a concentration of 0.1~0.5mol/L and precipitant solution with a concentration of 0.5~10mol/L, complexing agent solution I and complexing agent solution II the same agent; (3) Add complexing agent solution II as the bottom liquid and add the waste lithium cobalt oxide material obtained by calcination in step (1), and mix the nickel-cobalt-manganese mixed salt solution of step (2), complexing agent solution I, The precipitating agent solution is added to the reaction kettle by stream respectively, wherein the nickel-cobalt-manganese mixed salt solution is calculated according to the waste lithium cobalt oxide material and the theoretical lithium-rich manganese-based solid solution xLi[Li _1/3 Mn calculated from the nickel-cobalt-manganese mixed salt solution The mass ratio of _2/3 ]O ₂ ·(1-x)LiNi _1/3 Co _1/3 Mn _1/3 O ₂ is 100:0.1~10, and the flow rate of each solution is controlled during the reaction. The pH value of the liquid in the reaction kettle is controlled to be 9 to 11, the concentration of the complexing agent is controlled to be 0.1 to 0.5 mol/L, the reaction temperature is 20 to 95 ° C, and the reaction is performed for 10 to 260 min to obtain a slurry containing the composite precursor material. Wash and dry to obtain a composite precursor; (4) The composite precursor obtained in step (3) and the lithium source are uniformly mixed according to the molar ratio of Ni+Co+Mn:Li in the final product as 1:1.05~1.1, and calcined at 600~950℃ for 2~20h in an air atmosphere , and cooled to room temperature to obtain a positive electrode material. 2 . The method for preparing a high-voltage positive electrode material by using a waste lithium cobalt oxide battery according to claim 1 , wherein the x in step (2) is 0.1 to 0.9. 3 . 3. The method according to claim 1, wherein the nickel salt in step (2) is one of nickel sulfate, nickel chloride, nickel acetate, and nickel nitrate. One or several kinds are mixed in any proportion. 4. The method according to claim 1, wherein the cobalt salt in step (2) is one of cobalt sulfate, cobalt chloride, cobalt acetate, and cobalt nitrate. One or several kinds are mixed in any proportion. 5. The method according to claim 1, wherein the manganese salt in step (2) is one of manganese sulfate, manganese chloride, manganese acetate, and manganese nitrate. One or several kinds are mixed in any proportion. 6. The method for preparing a high-voltage positive electrode material by using waste lithium cobalt oxide batteries according to claim 1, wherein the complexing agent in step (2) is ammonia water, triethanolamine, citric acid, oxalic acid, ethylenediaminetetramine One or more of sodium acetate and ammonium bicarbonate are mixed in any proportion. 7 . The method for preparing a high-voltage positive electrode material by using a waste lithium cobalt oxide battery according to claim 1 , wherein the precipitating agent in step (2) is sodium hydroxide. 8 . 8. The method for preparing a high-voltage positive electrode material by using waste lithium cobalt oxide batteries according to claim 1, wherein the cleaning in step (3) is to use deionized water at 20 to 80°C to clean and precipitate to the final lotion. The pH value is lower than 10; the drying is drying at 60-150° C. for 6-60 hours. 9 . The method for preparing a high-voltage positive electrode material by using a waste lithium cobalt oxide battery according to claim 1 , wherein the lithium source in step (4) is lithium hydroxide or lithium carbonate. 10 .

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