CN108878836B - Method for directly preparing lithium zincate modified ternary cathode material from waste lithium battery cathode material - Google Patents

Abstract

The invention belongs to the technical field of preparation of ternary material precursors, and in particular relates to a method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material: separating the waste lithium ion battery from the positive electrode material; The solution is leached and filtered; carbonate is added to the filtrate to obtain lithium carbonate; the filter cake is leached with sulfuric acid to obtain a leaching solution; the molar ratio of nickel, cobalt and manganese in the leaching solution is adjusted; , co-precipitation to prepare ternary material precursor; then mixed with lithium carbonate and calcined to obtain ternary positive electrode material; zinc acetate, ethylene glycol plus ether, amines, and lithium methoxide were mixed, and ternary positive electrode material was added to obtain gel , and the ternary cathode material modified by lithium zincate is obtained by calcination. The ternary positive electrode material modified by the lithium zincate of the invention has strong structural stability, good electrochemical performance, reduced production cost, high product quality, and realizes the directional circulation of nickel, cobalt, manganese, and lithium resources.

Description

Direct preparation of lithium zincate modified ternary cathode materials from waste lithium battery cathode materials method of feeding

technical field

The invention belongs to the technical field of preparation of ternary material precursors, in particular to a method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material.

Background technique

Global energy consumption and carbon dioxide emissions show an exponential growth trend, and the demand for new renewable energy sources is also increasing. Since 2014, policies related to new energy vehicles have been introduced intensively. With the continuous progress of power battery technology, the entire industry chain has entered a period of rapid development, and the shipment of power batteries has shown a rapid growth trend. In 2018, the first batch of power batteries will be retired. tide. Ternary lithium-ion batteries are among the consumer batteries with high recycling value. In the next three years, the scale of decommissioning of ternary lithium-ion batteries will grow rapidly, and by 2020, the number of retired ternary lithium-ion batteries will reach more than 60Gwh. With the large-scale application of ternary lithium-ion batteries in passenger cars and logistics vehicles, the demand for cobalt has also increased significantly, and domestic cobalt prices have continued to rise. In addition, the cost per ton of nickel recovered from waste power batteries is less than 10,000 yuan, while the cost per ton of nickel produced by direct nickel ore is less than 60,000 yuan. Therefore, the cost of recycling metal raw materials is lower than the cost of direct mining. . Therefore, the recycling of ternary material batteries has the significance of reducing costs. However, after the ternary and lithium composite materials are made in the recycling process, the electrochemical performance is often greatly affected.

Chinese patent CN102751549A discloses a full-component recycling method for waste lithium-ion battery positive electrode materials. The method includes the following steps: (1) using a fluorine-containing organic acid aqueous solution to separate the active material and aluminum foil in the waste lithium-ion battery positive electrode material, liquid -Solid-solid separation to obtain leaching solution, lithium-containing active material and aluminum foil; (2) Lithium-containing active material is respectively subjected to high-temperature roasting and alkaline solution impurity removal treatment; (3) Leaching solution is respectively subjected to acid distillation to recover fluorine-containing organic acid, alkali addition Precipitation of impurity ions and co-precipitation of ammonium carbonate to prepare nickel-cobalt-manganese carbonate ternary precursor; (4) adjusting the composition of the treated active material and nickel-cobalt-manganese carbonate ternary precursor mixture, and adding a certain proportion of High temperature solid phase sintering after lithium carbonate is used to prepare nickel cobalt lithium manganate ternary composite cathode material. The invention firstly uses the fluorine-containing organic acid aqueous solution to leach the material, leaches all the nickel, cobalt, manganese, lithium and aluminum in the positive electrode material of the waste lithium ion battery, and obtains the nickel-cobalt lithium manganate ternary composite positive electrode material through precipitation, and mixes a certain amount of it. After the proportion of lithium carbonate, the nickel-cobalt lithium manganate ternary composite cathode material is prepared by high-temperature solid-phase sintering. The invention does not modify the nickel-cobalt lithium manganate ternary composite positive electrode material. The nickel-cobalt lithium manganate prepared in the present invention is characterized by XRD, and it is found that the crystal structure is complete, the impurity content is low, and the average particle size of the particles is 5.0-8.5μm, the specific surface area is 0.39-0.61m ² ·g ^-1 ; the first discharge capacity is 143-155mAh·g ^-1 after electrochemical detection, and it can be maintained above 130mAh·g ^-1 after 30 cycles , the electrochemical performance is good.

Chinese patent CN106848470A discloses a method for recovering and preparing ternary positive electrode materials from waste nickel-cobalt-manganese ternary lithium-ion batteries. The method includes the following steps: (1) disassembling and crushing waste nickel-cobalt-manganese ternary lithium-ion batteries , roasting, leaching to obtain the leachate containing Li, Ni, Co, Mn, the leachate is treated by the impurity-removing liquid; (2) adjust the molar ratio of Ni, Co, Mn in the impurity-removing liquid, then add alkali metal hydroxide And control the pH of the system ≥ 10, carry out primary precipitation, and obtain a turbid liquid with NCM hydroxide precipitated; (3) add carbonate to the turbid liquid of (2) to carry out secondary precipitation, and then separate the solid and liquid to obtain three. (4) calcining the ternary material precursor in air to obtain a ternary positive electrode material. The patent obtained is a ternary material. At room temperature, when discharged at a constant current of 0.5C, the specific capacity of the cycle is maintained at a maximum of 169mAh/g for 100 cycles.

However, the existing ternary cathode materials prepared from waste lithium battery cathode materials generally have the defect of poor stability. Therefore, there is an urgent need to develop a method for preparing a ternary positive electrode material from a waste lithium battery positive electrode material, and the prepared ternary positive electrode material has strong structural stability and good electrochemical performance.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method for directly preparing a lithium zincate modified ternary positive electrode material by utilizing the positive electrode material of waste lithium batteries, and the obtained ternary positive electrode material has strong structural stability, good electrochemical performance, simple process flow, and high production efficiency. low cost.

The method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material according to the present invention comprises the following steps:

(1) Disassemble the waste lithium-ion battery, separate the positive electrode sheet, roast, crush and sieve the positive electrode sheet, and separate the positive electrode material from the aluminum foil;

(2) leaching the positive electrode material with caustic alkali solution, and filtering to obtain filtrate and filter cake;

(3) add carbonate reaction in the filtrate, filter, obtain lithium carbonate solid and caustic alkali solution;

(4) leaching filter cake with sulfuric acid to obtain leachate and filter residue;

(5) adjust the molar ratio of nickel, cobalt and manganese in the leaching solution;

(6) under the protection of inert gas, the leaching solution after adjusting nickel, cobalt, manganese mol ratio, ammonia solution and the caustic alkali solution obtained in step (3) flow to the reactor containing ammonia solution, under the protection of inert gas Preparation of ternary material precursors by co-precipitation;

(7) after drying the ternary material precursor, the lithium carbonate solid obtained in step (3) is mixed and roasted to obtain a ternary positive electrode material;

(8) Use zinc acetate as the zinc source, ethylene glycol methyl ether or the mixture of ethylene glycol methyl ether and water as the solvent, and amines as the stabilizer, mix with lithium methoxide, heat up, add the ternary positive electrode material, let it stand, The gel is obtained, and the ternary cathode material modified by lithium zincate is obtained by calcination.

in:

In step (1), the molar ratio of nickel, cobalt and manganese in the positive electrode material is one of 5:2:3, 3:3:3, 6:2:2, 8:1:1 or 4:2:2. one or more; the roasting temperature is 450-700°C, and the roasting time is 10-60min.

In step (2), the caustic is sodium hydroxide, calcium hydroxide, potassium hydroxide or lithium hydroxide; the concentration of the caustic solution is 0.5-3 mol/L; the leaching temperature is 10-100 ° C, and the leaching time is 0.5- 2h, the liquid-solid ratio of the caustic alkali solution to the cathode material during leaching is 4-12:1.

In step (3), the carbonate is potassium carbonate or sodium carbonate, the reaction temperature is 20-90°C, and the reaction time is 10-60min.

In step (3), the caustic alkali solution is recovered and returned to the process for recycling.

In step (4), the molar concentration of sulfuric acid is 0.5-3.5 mol/L; the leaching temperature is 50-100° C., the leaching time is 30-240 min, and the liquid-solid ratio of sulfuric acid to the filter cake is 4-12:1.

In step (5), in the adjusted leachate, the concentration of nickel is 1-4 mol/L, and the molar ratios of nickel, cobalt and manganese are 5:2:3, 3:3:3, 6:2:2, 8: 1:1 or 4:2:4; when adjusting the molar ratio of nickel, cobalt and manganese in the leaching solution, add it in the form of sulfate, nitrate or hydrochloride of nickel, cobalt and manganese.

In step (6), the inert gas is nitrogen gas or argon gas; the molar concentration of the ammonia solution is 0.5-2.5mol/L, the molar concentration of the caustic alkali solution obtained in step (3) is 0.5-2.5mol/L, and the nickel, cobalt, The addition rate of the leachate after the manganese molar ratio is 1-8ml/min, the addition rate of the ammonia solution is 1-8ml/min, and the addition rate of the caustic alkali solution is 2-20ml/min; The volume of the ammonia solution in the kettle accounts for 1/5-1/4 of the total volume of the reactor.

In step (7), the drying temperature is 70-120°C, and the drying time is 10-20 hours; the calcination is calcined at 30-650°C for 3-6h, and then calcined at 700-900°C for 7-15h with argon.

In step (8), the mass ratio of ethylene glycol methyl ether and water in the mixture of ethylene glycol methyl ether and water is 1.5-2.5:1.

In step (8), the amines are ammonium monoacetate, the molar ratio of zinc acetate to ammonium monoacetate is 0.5-1.5:1, the molar ratio of lithium methylate to zinc acetate is 2-2.5:1, ethylene glycol methyl ether and zinc acetate The molar ratio is 2-3:1.

In step (8), use zinc acetate as zinc source, ethylene glycol methyl ether or the mixture of ethylene glycol methyl ether and water as solvent, amines as stabilizer, after mixing with lithium methylate, stirring at normal temperature for 10-40min, warming up to After 50-90°C, add the ternary cathode material, stir for 1.5-3h, stand for 30-50h to obtain a gel, and bake at 700-900°C for 60-180min to obtain the ternary cathode material modified by lithium zincate.

The chemical reaction equation in the gel process when the lithium zincate modified ternary positive electrode material is prepared by the present invention is as follows:

Zn(CH ₃ COO) ₂ +2H ₂ O=Zn(OH) ₂ +2CH ₃ COOH;

2n Zn(OH) ₂ =(Zn-O-Zn) _n +2n H ₂ O+0.5nO ₂ ;

(Zn-O-Zn) _n + 4n LiOCH ₃ +6.5nO ₂ =2n Li ₂ ZnO ₂ +4n CO ₂ +6n H ₂ O.

The beneficial effects of the present invention are as follows:

In order to overcome the shortage of nickel-cobalt-manganese-lithium resources and the pollution of waste and old batteries, the present invention provides a method for directly preparing a ternary positive electrode material modified by lithium zincate by using the positive electrode material of waste and old lithium batteries. solution, separate the positive electrode sheet, and then separate the positive electrode material from the positive electrode sheet. The positive electrode material is first leached with caustic alkali solution, and the metal lithium in the filtrate is precipitated with carbonate to realize lithium recovery; then the filter cake is leached with sulfuric acid to adjust the nickel The molar concentration of cobalt and manganese, and then under the protection of inert gas, the leaching solution, ammonia solution and caustic alkali solution after adjusting the molar ratio of nickel, cobalt and manganese are co-flowed into the reactor, and ternary materials are prepared by co-precipitation under the protection of inert gas For the precursor, after drying the ternary material precursor, it is mixed and calcined with lithium carbonate solid to obtain a ternary positive electrode material; the ternary positive electrode material is then mixed with a mixture of zinc acetate, ethylene glycol methyl ether, ammonium monoacetate, and lithium methoxide, The ternary positive electrode material modified by lithium zincate is obtained by roasting. The obtained lithium zincate modified ternary cathode material has good electrochemical performance.

The caustic alkali solution of the present invention cannot leach nickel, cobalt and manganese, but can only leach lithium, thereby realizing low-temperature recovery of lithium. No prior art involves firstly recovering lithium at low temperature before recovering nickel, cobalt, and manganese. The present invention improves the recovery of lithium. Recovery rate; in the present invention, because the precipitation speed of nickel, cobalt and caustic alkali solution is far faster than that of manganese and caustic alkali solution, a part of the ammonia solution is first added to the reactor in advance, and then the remaining ammonia solution and adjustment nickel, The leachate and caustic solution after the molar ratio of cobalt and manganese are added into the reaction kettle in parallel. Nickel and cobalt first react with ammonia water to form a complex, and then the complex reacts with the caustic solution to reduce nickel, cobalt and caustic. The precipitation speed of the solution ensures the simultaneous precipitation of manganese, nickel and cobalt, and also ensures the uniformity of the distribution of nickel, cobalt and manganese in the ternary material.

In the present invention, under the conditions that ethylene glycol methyl ether or a mixture of ethylene glycol methyl ether and water is used as a solvent and amines are used as stabilizers, zinc acetate is first hydrolyzed to zinc hydroxide, and zinc hydroxide reacts with lithium methylate to generate lithium zincate , the ternary positive electrode material is modified by lithium zincate, and the ternary positive electrode material modified by lithium zincate is obtained by roasting, which improves the electrochemical performance of the ternary positive electrode material.

When the ternary cathode material is charged to a high voltage, a large amount of Co ³⁺ and Mn ²⁺ in the ternary cathode material will be oxidized into Co ⁴⁺ and Mn ⁴⁺ , thereby forming oxygen defects, which will weaken the bond between the transition metal and oxygen. binding force, so that high-valent ions dissolve into the electrolyte. After Li ₂ ZnO ₂ coating modification, during the charging and discharging process, the interface between the ternary cathode material and Li ₂ ZnO ₂ will rearrange, thereby reducing the formation of oxygen defects and improving the structural stability of the ternary cathode material. .

The method directly utilizes the nickel-cobalt-manganese material obtained in the recycling process of the waste lithium ion battery to synthesize the nickel-cobalt-manganese ternary material modified by lithium zincate, and is especially suitable for providing high-quality nickel source, cobalt source and manganese source for the production of lithium ion battery material. . The invention uses waste lithium-ion batteries as raw materials, has low cost, high product quality and good economy, and realizes the directional circulation of nickel-cobalt-manganese-lithium resources. The invention can bring huge environmental benefits, social benefits and economic benefits after the large-scale production is formed.

Description of drawings

Fig. 1 is the SEM image of the ternary cathode material modified by lithium zincate in Example 1;

Fig. 2 is the time-current and time-voltage diagrams of the ternary positive electrode material modified by lithium zincate in Example 1;

Fig. 3 is the SEM image of the ternary positive electrode material modified by lithium zincate in Example 2;

4 is a capacity-voltage diagram of a coin cell assembled from a ternary positive electrode material modified by lithium zincate in Example 2;

Fig. 5 is the SEM image of the ternary positive electrode material modified by lithium zincate in Example 3;

6 is a charge-discharge efficiency diagram of a button battery assembled from a ternary positive electrode material modified by lithium zincate in Example 3;

Fig. 7 is the SEM image of the ternary cathode material modified by lithium zincate in Example 4;

8 is a time-current and time-voltage diagram of the lithium zincate modified ternary cathode material in Example 4. FIG.

Detailed ways

The present invention will be further described below in conjunction with the embodiments.

Example 1

The positive electrode sheet separated from the dismantling of the waste lithium-ion battery was calcined at 650 ° C for 15 minutes, and the obtained calcined product was crushed on a crusher, sieved, and the positive electrode material was separated from the aluminum foil; the molar ratio of nickel, cobalt, and manganese in the positive electrode material was 5:2:3 and 8:1:1;

The positive electrode material was leached with 2.5mol/L sodium hydroxide solution at 95°C for 40min, the liquid-solid ratio of the sodium hydroxide solution and the positive electrode material during leaching was 10:1, and the filtrate and filter cake were obtained by filtration;

To the filtrate, add sodium carbonate whose mole number is 0.5 times the mole number of lithium ions, and stir and react at 25°C for 60 minutes to generate turbid liquid, and filter to obtain lithium carbonate solid and filtrate. The filtrate is a 2.2 mol/L sodium hydroxide solution; lithium The recovery rate of 94.6%;

The filter cake was leached with a 1.0 mol/L sulfuric acid solution at 50°C for 220 min, and the liquid-solid ratio of the sulfuric acid solution and the filter cake during leaching was 11:1 to obtain a leachate;

The nickel ion concentration in the leaching solution was adjusted to be 1.5 mol/L, and cobalt chloride and manganese chloride were added simultaneously, so that the molar ratio of nickel, cobalt and manganese in the solution was 6:2:2;

Add 200 ml of 0.6 mol/L ammonia solution to the reaction kettle, and the stirring speed is 800 r/min. Add 0.6 mol/L ammonia solution, the leaching solution after adjusting the molar ratio of nickel, cobalt and manganese, and the hydrogen whose concentration is 2.2 mol/L. The sodium oxide solution was added to the reaction kettle in a co-current flow, and nitrogen was used as an atmosphere protection for co-precipitation, and then the solid-liquid separation was followed by drying to obtain a ternary material precursor; wherein the addition rate of ammonia water was 3ml/min, and the nickel, cobalt, The dripping speed of the leachate after the manganese molar ratio is 5ml/min, and the adding speed of the sodium hydroxide solution is 10ml/min;

After drying the ternary material precursor at 80°C for 20 hours, it is mixed with the lithium carbonate solid obtained above, first calcined at 100°C for 6h, and then calcined at 700°C for 14h in argon to obtain a ternary cathode material;

Use zinc acetate as zinc source, ethylene glycol methyl ether as solvent, ammonium monoacetate as stabilizer, mix with lithium methoxide, stir at room temperature for 15min, heat up to 60°C, add ternary cathode material, stir for 2.5h, stand for 50h, The gel was obtained, and calcined at 750° C. for 150 min to obtain a ternary cathode material modified by lithium zincate, wherein the molar ratio of zinc acetate to ammonium monoacetate was 0.5:1, the molar ratio of lithium methoxide to zinc acetate was 2:1, and the The molar ratio of methyl alcohol ether to zinc acetate was 2:1. The SEM images, time-current and time-voltage diagrams of the lithium zincate modified ternary cathode material are shown in Figures 1 and 2. Among them, the upper part of FIG. 2 is a voltage diagram, and the lower part is a current diagram.

Example 2

The positive electrode sheet separated from the dismantling of the waste lithium ion battery was calcined at 580 ° C for 30 minutes, and the obtained calcined product was crushed on a crusher, sieved, and the positive electrode material was separated from the aluminum foil; the molar ratio of nickel, cobalt, and manganese in the positive electrode material was 3:3:3 and 4:2:2;

The positive electrode material was leached with 2.0 mol/L potassium hydroxide solution at 75°C for 60 min, and the liquid-solid ratio of the potassium hydroxide solution to the positive electrode material during leaching was 8:1, and the filtrate and filter cake were obtained by filtration;

To the filtrate, add potassium carbonate whose mole number is 0.5 times the mole number of lithium ions, stir and react at 40 ° C for 50 min, generate a turbid liquid, and filter to obtain lithium carbonate solid and filtrate, and the filtrate is 1.5 mol/L potassium hydroxide solution; lithium The recovery rate of 94.2%;

The filter cake was leached with 1.5 mol/L sulfuric acid solution at 65°C for 180 min, and the liquid-solid ratio of the sulfuric acid solution and the filter cake during leaching was 9:1 to obtain a leachate;

The nickel ion concentration in the leaching solution was adjusted to be 2.0 mol/L, and cobalt sulfate and manganese sulfate were added simultaneously, so that the molar ratio of nickel, cobalt, and manganese in the solution was 4:2:4;

Add 200 ml of 1.2 mol/L ammonia solution to the reaction kettle, and the stirring speed is 900 r/min. The 1.2 mol/L ammonia solution, the leaching solution after adjusting the molar ratio of nickel, cobalt and manganese, and the above-mentioned hydrogen with a concentration of 1.5 mol/L are added. Potassium oxide solution was added to the reaction kettle in parallel, and argon was used as atmosphere protection, co-precipitation, and then solid-liquid separation and drying to obtain a ternary material precursor; wherein the addition rate of ammonia water was 5ml/min, and the nickel and cobalt were adjusted. The rate of addition of the leachate after the molar ratio of manganese is 3ml/min, and the rate of addition of potassium hydroxide solution is 5ml/min;

After drying the ternary material precursor at 95 ℃ for 18 hours, it is mixed with the lithium carbonate solid obtained above, first calcined at 280 ℃ for 5 hours, and then calcined at 780 ℃ for 12 hours in argon to obtain a ternary cathode material;

Use zinc acetate as zinc source, ethylene glycol methyl ether as solvent, ammonium monoacetate as stabilizer, mix with lithium methoxide, stir at room temperature for 25min, heat up to 70°C, add ternary cathode material, stir for 2.0h, stand for 45h, The gel was obtained, calcined at 800° C. for 120 min to obtain a ternary cathode material modified by lithium zincate, wherein the molar ratio of zinc acetate to ammonium monoacetate was 0.8:1, the molar ratio of lithium methoxide to zinc acetate was 2.2:1, and the The molar ratio of methyl alcohol ether to zinc acetate was 2.2:1. Figure 3 and Figure 4 show the SEM image of the ternary cathode material modified by lithium zincate and the capacity-voltage diagram of the assembled coin battery.

Example 3

The positive electrode sheet separated from the dismantling of the waste lithium ion battery was calcined at 500 ° C for 45 minutes, and the obtained calcined product was crushed on a crusher, sieved, and the positive electrode material was separated from the aluminum foil; the molar ratio of nickel, cobalt, and manganese in the positive electrode material was 8:1:1 and 4:2:2;

The positive electrode material was leached with a 1.5 mol/L potassium hydroxide solution at 50°C for 100 min, and the liquid-solid ratio of the potassium hydroxide solution to the positive electrode material during leaching was 6:1, and filtered to obtain a filtrate and a filter cake;

The filtrate was added with potassium carbonate whose mole number was 0.5 times the mole number of lithium ions, and the reaction was stirred at 65° C. for 30 min to generate a turbid liquid, which was filtered to obtain a lithium carbonate solid and a filtrate. The filtrate was a 1.0 mol/L potassium hydroxide solution; lithium The recovery rate of 94.5%;

The filter cake was leached with 2.0 mol/L sulfuric acid solution at 80°C for 120 min, and the liquid-solid ratio of the sulfuric acid solution and the filter cake during leaching was 7:1 to obtain a leachate;

The nickel ion concentration in the leaching solution was adjusted to be 3.5 mol/L, and cobalt nitrate and manganese nitrate were added simultaneously, so that the molar ratio of nickel, cobalt and manganese in the solution was 8:1:1;

200ml of 1.8mol/L ammonia solution was added to the reaction kettle, and the stirring speed was 700r/min. The 1.8mol/L ammonia solution, the leaching solution after adjusting the molar ratio of nickel, cobalt and manganese, and the above-mentioned hydrogen with a concentration of 1.0mol/L were added. Potassium oxide solution was added to the reaction kettle in parallel, and argon was used for atmosphere protection, co-precipitation, and drying after solid-liquid separation to obtain a ternary material precursor; wherein the addition rate of ammonia water was 7ml/min, and the nickel and cobalt were adjusted at a rate of 7 ml/min. The dropping rate of the leachate after the molar ratio of manganese is 6ml/min, and the adding rate of potassium hydroxide solution is 15ml/min;

After drying the ternary material precursor at 110°C for 15 hours, mix it with the lithium carbonate solid obtained above, first calcinate at 450°C for 4h, and then pass argon for 10h at 820°C to obtain a ternary cathode material;

Use zinc acetate as zinc source, ethylene glycol methyl ether and water as solvent, ammonium monoacetate as stabilizer, mix with lithium methoxide, stir at room temperature for 30min, heat up to 75°C, add ternary cathode material, stir for 1.5h, and let stand 40h to obtain a gel, calcined at 850°C for 90min to obtain a lithium zincate modified ternary cathode material, wherein the mass ratio of ethylene glycol methyl ether and water in the mixture of ethylene glycol methyl ether and water is 1:1; The molar ratio of zinc acetate to ammonium monoacetate was 1.2:1, the molar ratio of lithium methoxide to zinc acetate was 2.4:1, and the molar ratio of ethylene glycol methyl ether to zinc acetate was 2.6:1. Figure 5 and Figure 6 show the SEM image of the ternary cathode material modified by lithium zincate and the charge and discharge efficiency of the assembled button battery.

Example 4

The positive electrode sheet separated from the dismantling of the waste lithium ion battery was calcined at 450 ° C for 60 min, the obtained calcined product was crushed on a crusher, sieved, and the positive electrode material was separated from the aluminum foil; the molar ratio of nickel, cobalt, and manganese in the positive electrode material was is 6:2:2;

The positive electrode material was leached with 0.7 mol/L calcium hydroxide solution at 30°C for 120 min, and the liquid-solid ratio of the calcium hydroxide solution to the positive electrode material during leaching was 5:1, and the filtrate and filter cake were obtained by filtration;

The filtrate was added with potassium carbonate whose mole number was 0.5 times the mole number of lithium ions, and the reaction was stirred at 80° C. for 20 min to generate a turbid liquid, which was filtered to obtain lithium carbonate solid and filtrate. The filtrate was a 0.5 mol/L calcium hydroxide solution; lithium The recovery rate of 94.6%;

The filter cake was leached with 3.5mol/L sulfuric acid solution at 95°C for 60min, and the liquid-solid ratio of the sulfuric acid solution and the filter cake during leaching was 5:1 to obtain a leachate;

The nickel ion concentration in the leaching solution was adjusted to be 4.0 mol/L, and cobalt nitrate and manganese nitrate were added simultaneously, so that the molar ratio of nickel, cobalt and manganese in the solution was 5:2:3;

200ml of 2.4mol/L ammonia solution was added to the reaction kettle, and the stirring speed was 800r/min. The 2.4mol/L ammonia solution, the leaching solution after adjusting the molar ratio of nickel, cobalt and manganese, and the hydrogen whose above-mentioned concentration was 0.5mol/L were added. The calcium oxide solution was added into the reaction kettle in parallel, protected by nitrogen atmosphere, co-precipitated, and dried after solid-liquid separation to obtain a ternary material precursor; wherein the addition rate of ammonia water was 2ml/min, and the nickel, cobalt, The dripping speed of the leachate after the manganese molar ratio is 7ml/min, and the adding speed of calcium hydroxide solution is 18ml/min;

After drying the ternary material precursor at 118°C for 12 hours, mix it with the lithium carbonate solid obtained above, first calcinate at 550°C for 3h, and then pass argon for 8h at 890°C to obtain a ternary cathode material;

Zinc acetate was used as the zinc source, the mixture of ethylene glycol methyl ether and water was used as the solvent, and ammonium monoacetate was used as the stabilizer. After mixing with lithium methylate, the mixture was stirred at room temperature for 35 minutes. Let stand for 35h to obtain a gel, calcined at 900°C for 65min to obtain a ternary cathode material modified by lithium zincate, wherein the mass ratio of ethylene glycol methyl ether and water in the mixture of ethylene glycol methyl ether and water is 2: 1. The molar ratio of zinc acetate to ammonium monoacetate is 1.5:1, the molar ratio of lithium methoxide to zinc acetate is 2.3:1, and the molar ratio of ethylene glycol methyl ether to zinc acetate is 2.8:1. The SEM images, time-current and time-voltage diagrams of the lithium zincate modified ternary cathode material are shown in Figures 7 and 8. The upper part of FIG. 8 is a voltage diagram, and the lower part is a current diagram.

Claims (10)

1. a method utilizing waste lithium battery positive electrode material to directly prepare the ternary positive electrode material modified by lithium zincate, is characterized in that comprising the following steps: (1) Disassemble the waste lithium-ion battery, separate the positive electrode sheet, roast, crush and sieve the positive electrode sheet, and separate the positive electrode material from the aluminum foil; (2) Leach the positive electrode material with caustic alkali solution, and filter to obtain filtrate and filter cake; (3) Add carbonate reaction in the filtrate, filter to obtain lithium carbonate solid and caustic alkali solution; (4) leaching the filter cake with sulfuric acid to obtain leachate and filter residue; (5) Adjust the molar ratio of nickel, cobalt and manganese in the leaching solution; (6) Under the protection of inert gas, the leaching solution after adjusting the molar ratio of nickel, cobalt and manganese, the aqueous ammonia solution and the caustic alkali solution obtained in step (3) are co-flowed into the reaction kettle containing the aqueous ammonia solution, under the protection of inert gas. Preparation of ternary material precursors by co-precipitation; (7) After drying the ternary material precursor, it is mixed and calcined with the solid lithium carbonate obtained in step (3) to obtain a ternary positive electrode material; (8) Use zinc acetate as the zinc source, ethylene glycol methyl ether or a mixture of ethylene glycol methyl ether and water as the solvent, and amines as the stabilizer, mix with lithium methoxide, heat up, add the ternary positive electrode material, let it stand, The gel is obtained, and the ternary cathode material modified by lithium zincate is obtained by roasting; In step (2), the leaching temperature is 10-100°C; In step (2), the caustic is sodium hydroxide, calcium hydroxide or potassium hydroxide; In step (3), carbonate is potassium carbonate or sodium carbonate; In step (8), the amines are ammonium monoacetate. 2. The method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material according to claim 1, characterized in that: in step (1), the moles of nickel, cobalt, and manganese in the positive electrode material are The ratio is one or more of 5:2:3, 3:3:3, 6:2:2, 8:1:1 or 4:2:2; the roasting temperature is 450-700℃, and the roasting time is 10-60min. 3. The method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material according to claim 1, characterized in that: in step (2), the concentration of the caustic solution is 0.5-3mol/ L; The leaching time is 0.5-2h, and the liquid-solid ratio of the caustic alkali solution to the positive electrode material during leaching is 4-12:1. 4. The method for directly preparing a lithium zincate-modified ternary positive electrode material from a waste lithium battery positive electrode material according to claim 1, wherein in step (3), the reaction temperature is 20-90°C, and the reaction time is 20-90°C. For 10-60min. 5. The method for directly preparing a lithium zincate-modified ternary positive electrode material from a waste lithium battery positive electrode material according to claim 1, wherein in step (4), the molar concentration of sulfuric acid is 0.5-3.5 mol/ L; the leaching temperature is 50-100°C, the leaching time is 30-240min, and the liquid-solid ratio of sulfuric acid to the filter cake is 4-12:1. 6. The method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material according to claim 1, wherein in step (5), in the adjusted leachate, the concentration of nickel is 1-4mol/L, the molar ratio of nickel, cobalt and manganese is 5:2:3, 3:3:3, 6:2:2, 8:1:1 or 4:2:4; adjust the nickel, When the molar ratio of cobalt and manganese is used, it is added in the form of sulfate, nitrate or hydrochloride of nickel, cobalt and manganese. 7. The method for directly preparing a lithium zincate-modified ternary positive electrode material by using a waste lithium battery positive electrode material according to claim 1, wherein in step (6), the inert gas is nitrogen or argon; The molar concentration is 0.5-2.5mol/L, the molar concentration of the caustic alkali solution obtained in step (3) is 0.5-2.5mol/L, and the addition rate of the leachate after adjusting the molar ratio of nickel, cobalt and manganese is 1-8ml /min, the rate of addition of the aqueous ammonia solution is 1-8ml/min, and the rate of addition of the caustic solution is 2-20ml/min; before the co-current, the volume of the aqueous ammonia solution in the reaction kettle containing the aqueous ammonia solution accounts for 2% of the total volume of the reaction kettle 1/5-1/4. 8. The method for directly preparing a lithium zincate-modified ternary positive electrode material from a waste lithium battery positive electrode material according to claim 1, characterized in that: in step (7), the drying temperature is 70-120°C, and the drying time is 70-120°C. For 10-20 hours; roasting is roasting at 30-650 ℃ for 3-6 hours, and 700-900 ℃ for 7-15 hours with argon. 9 . The method for directly preparing a lithium zincate-modified ternary positive electrode material from a waste lithium battery positive electrode material according to claim 1 , wherein in step (8), the molar ratio of zinc acetate to ammonium monoacetate is: 10 . 0.5-1.5:1, the molar ratio of lithium methoxide to zinc acetate is 2-2.5:1, and the molar ratio of ethylene glycol methyl ether to zinc acetate is 2-3:1. 10 . The method for directly preparing a lithium zincate-modified ternary positive electrode material from a waste lithium battery positive electrode material according to claim 1 , wherein in step (8), zinc acetate is used as the zinc source, and ethylene glycol is used as the zinc source. 11 . The mixture of methyl ether or ethylene glycol methyl ether and water as solvent, amine as stabilizer, mixed with lithium methoxide, stirred at room temperature for 10-40min, heated to 50-90℃, then added ternary cathode material, stirred for 1.5-3h, Let stand for 30-50h to obtain a gel, which is calcined at 700-900° C. for 60-180min to obtain a ternary cathode material modified by lithium zincate.

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