CN1332475C - Production of LixCoO2 from recovering waste lithium ionic battery - Google Patents

Abstract

The invention discloses a method for recovering and preparing Li _x CoO ₂ from discarded lithium ion batteries, which belongs to the preparation process of liquid-phase coating precipitation composite powder. The method comprises the steps of: cutting the battery, separating the positive electrode material and cutting the positive electrode material into small pieces; soaking the cut pieces in N-methyl-2-pyrrolidone liquid, heating and separating the active material Li _x CoO ₂ to obtain black powder; black powder dispersed in nitric acid solution or hydrochloric acid solution, filtered to obtain nitrate solution or chloride solution containing Co ²⁺ , Li ⁺ ions; add NH ₃ ·H to the acidic leaching solution containing Co ²⁺ , Li ⁺ ions ₂ O to form a blue precipitate, and at the same time add a surfactant and LiOH to adjust the concentration of Li ⁺ ions in the suspension; filter and dry the precipitate in the suspension, and roast it at a temperature of 600-900°C, that is Li _x CoO ₂ powder is obtained. The present invention can recover at least 95% of cobalt and at least 93% of lithium from waste lithium-ion batteries to prepare Li _x CoO ₂ powder with a particle size of 0.2-1.0 μm and a specific surface area of 2.0-6.0 m ² ·g ^-1 .

Description

Reclaim and prepare LixCoO2 method from waste lithium-ion batteries

technical field

The invention relates to a method for recovering and preparing _LixCoO2 from discarded lithium ion batteries, which belongs to the _technology of chemical separation and preparation of inorganic powder. In particular, the process involved in this technology is a liquid-phase coating precipitation composite powder preparation process.

Background technique

The positive electrode material of lithium ion battery is made of active material LiCoO ₂ , carbon black, acetylene black, and binder adhered to the aluminum foil in a certain proportion. The content of each part of the positive electrode material is shown in Table 1:

Table 1 Composition of cathode materials for lithium-ion batteries

substance _LiCoO2 carbon black, acetylene black Binder aluminum foil Content (wt.%) 76.80 9.03 4.52 9.65

The disposal of scrapped lithium-ion batteries usually faces the following problems: First, the surface of the positive and negative electrodes of scrapped lithium-ion batteries usually contains a small amount of elemental lithium. Since metal lithium in the elemental state is highly flammable and explosive, This is a safety issue that requires special attention in battery disposal; in addition, cobalt is a heavy metal that can be harmful to the environment if not handled properly. Therefore, the reasonable disposal of scrap lithium-ion batteries is of great significance to protect the environment.

In foreign research work on the recovery of lithium-ion secondary batteries, the more representative technology is the technology of recovering cobalt from waste lithium-ion secondary batteries, which has been jointly researched and developed by Sony Corporation of Japan and Sumitomo Metal Mining Corporation. Incinerate the battery first to remove organic matter, then screen, remove iron and copper, heat the residual powder and dissolve it in acid, and extract it with an organic solvent to extract cobalt oxide. This product can be used as a raw material for pigments and coatings industries. . However, the above methods still have certain deficiencies: First, the method of incineration to remove organic matter needs to be equipped with flue gas purification equipment, otherwise it will easily cause air pollution; in addition, under the condition of heating, the "residual powder" is dissolved with hydrochloric acid to prevent corrosion of the equipment The requirements are high and the operating environment is harsh.

There are also methods for recycling waste lithium-ion batteries by chemical leaching: the method proposed by Japanese Patent JP 11185834, which is characterized in that the positive electrode material of the battery is eroded with hydrochloric acid, oxalate is used as a precipitant, and the formed cobalt oxalate precipitate is used as a recovery method. Product; the method proposed in Japanese Patent JP 11054159 is to corrode the positive electrode material with nitric acid, adjust the pH value with lithium hydroxide, and take the hydroxide of metal cobalt as the recovery product; the method proposed in Chinese Patent CN 1402376A is to contain sodium chloride Aqueous hydrochloric acid solution dissolves spent lithium-ion batteries

Contents of the invention

The purpose of the present invention is to provide a method for recovering and preparing Li _x CoO ₂ from discarded lithium ion batteries. The Li _x CoO ₂ powder prepared by the method has a high specific surface area and a hexagonal layered structure crystal with an R3m space group structure.

The present invention is achieved through the following technical solutions, a method of reclaiming and preparing Li _{x CoO} from discarded lithium ion batteries (X=0.95～1.05 in the formula), which is characterized in that it comprises the following steps:

(1) Cutting of battery

Cut the battery in water to separate the positive electrode material from other components, and cut the positive electrode material into small pieces;

(2) Soak the cut positive plate fragments in N-methyl-2-pyrrolidone (NMP) liquid, 1.5~2.0L of NMP is needed for every 1kg of positive electrode fragments, heat the liquid to 85~100℃, and after 15~30 Minutes, the positive electrode active material Li _x CoO ₂ and carbon black adhering to the aluminum foil can fall off into the liquid, take out the aluminum foil, filter, and recover NMP for recycling, wash the filtered powder with water, filter and dry A black powder can be obtained;

(3) Disperse the obtained black powder in nitric acid solution of mass concentration 10～30% or mass concentration 10～30% hydrochloric acid solution, every 0.1～0.5kg powder needs nitric acid solution or hydrochloric acid solution 1～1.5L, and add to Add 10-50ml of hydrogen peroxide solution with a mass concentration of 1-5% dropwise into the solution, stir for about 40 minutes, and filter to obtain a nitrate solution or chloride solution containing Co2 ⁺ and Li ⁺ ions; by accurately weighing the The amount of carbon black obtained can calculate the concentration of Co ²⁺ and Li ⁺ ions in the solution, and can also measure the concentration of Co ²⁺ ions in the solution by EDTA titration, and measure the concentration of Co 2+ ions in the solution by the fluoride ion selective electrode method. concentration of Li ⁺ ions;

(4) At room temperature, slowly add NH ₃ ·H ₂ O to the acidic leaching solution containing Co ²⁺ and Li ⁺ ions prepared in step (3), adjust and control the pH of the solution to 8-11, and form a blue color Precipitation, while adding one of the following surfactants: polyacrylic acid (PAA), polyethylene glycol (PEG), polymethacrylic acid (PMAA), polyethyleneimine (PEI), the amount added is the quality of the original black powder 1% to 5% of the concentration, keep stirring for 8 to 12 hours;

(5) water bath heating step (4) solution to 80～95 ℃, adjust the concentration of Li ⁺ ions in the suspension by adding LiOH, and make the molar ratio Li: Co=1～1.10: 1; While vigorously stirring , add dropwise a NH ₄ HCO ₃ solution with a concentration of 2 to 5 mol/L in the suspension, the amount added is to make the molar number of NH ₄ HCO ₃ greater than 1.6 to 2 times the molar number of Li ⁺ in the solution, and keep stirring 2 to 4 hours;

(6) Filter and dry the precipitate in the suspension in step (5), and calcinate at a temperature of 600-900° C. for 7-12 hours to obtain Li _x CoO ₂ powder.

Using the above method, at least 95% of cobalt and at least 93% of lithium can be recovered from waste lithium-ion batteries; Li _x with a particle size of about 0.2-1.0 μm and a specific surface area of 2.0-6.0 m ² ·g ^-1 can be prepared CoO ₂ powder.

Description of drawings

Fig. 1 is an X-ray diffraction spectrum of Li _x CoO ₂ powder prepared in Example 1 of the present invention.

Fig. 2 is an X-ray diffraction spectrum of Li _x CoO ₂ powder prepared in Example 2 of the present invention.

Detailed ways

example 1.

Take various types of lithium-ion batteries, cut the battery in water, separate the positive electrode material from other components, weigh 150g of the positive plate, cut the positive plate into pieces smaller than 2cm×2cm, and put these pieces at room temperature Put into 300ml of N-methyl-2-pyrrolidone (NMP) liquid, heat the liquid to 85°C, and after 30 minutes, all the powder substances (including the positive electrode active material Li _x CoO) adhered on the aluminum foil can be made ₂ and carbon black) fall off into the liquid, take out the aluminum foil, filter the liquid and reclaim NMP (recyclable), wash the filtered powder with clear water, dry to obtain 127g (theoretical value should be 128.7g) black powder; Put the black powder into 1.4L concentration of 15% (wt.) nitric acid solution, and while stirring, dropwise add concentration of 5% (wt.) H ₂ O ₂ solution 0.18L in this solution, continue to stir About 40 minutes, filter to obtain the nitrate solution containing ^Co2+ , Li ⁺ ions, the quality of the cobalt in the solution measured by EDTA titration is 65.90g (theoretical value is 69.36g), and the leaching rate of cobalt is 95.05% , the mass of lithium in the solution measured by the fluoride ion selective electrode method is 7.76g (theoretical value is 8.23g), the leaching rate of lithium is 94.34%, and the mol ratio of the metal ion in the solution is Li ⁺ : Co ²⁺ = 0.95:1; slowly add NH ₃ ·H ₂ O to the above solution, adjust and control the pH to 9, and form a blue precipitate, at the same time add 2.5 g of polyethylene glycol with a molecular weight of 1000, continue stirring for 10 hours, and heat the above solution in a water bath Suspend the liquid to 90°C, add 0.12mol LiOH to the suspension, add dropwise 370ml of NH ₄ HCO ₃ solution with a concentration of 3 mol/L while stirring vigorously, keep stirring for 3 hours, and filter the precipitate in the suspension and drying to obtain a precursor powder of the synthesized product, which is calcined at a temperature of 700° C. for 8 hours to obtain a Li _x CoO ₂ powder with a grain size of less than 1 μm. The crystal phase analysis of the obtained powder is shown in the X-ray diffraction diagram of Figure 1, and the lattice parameters of the powder are shown in Table 2, indicating that the prepared Li _x CoO _The powder has a regular hexagonal layered structure; The specific surface area of the powder of sample 1 measured by nitrogen BET multilayer adsorption method was 7.95m ² ·g ^-1 ; the primary discharge capacity of the prepared Li _x CoO ₂ was 142mAh·g ^-1 .

Table 2 The lattice parameters of different samples Li _x CoO ₂ , the specific surface area of the powder and the discharge capacity

sample a (A) c(A) c/a I ₍₀₀₃₎ /I ₍₁₀₄₎ Specific surface area (m ² ·g ^-1 ) Discharge capacity (mAh·g ^-1 ) Sample 1 2.8158 14.0484 4.9904 2.5316 7.95 142 Sample 2 2.8167 14.0783 4.9989 1.9081 5.12 147

Example 2.

The precursor of the synthesized product was prepared by the same process as in Example 1, and the precursor was calcined at a temperature of 800°C for 8 hours to obtain a Li _x CoO ₂ powder with a grain size of less than 1 μm. The crystal phase analysis of the obtained powder is shown in the X-ray diffraction diagram of Figure 2, and the lattice parameters of the powder are shown in Table 2, indicating that the prepared Li _x CoO _The powder has a regular hexagonal layered structure; The specific surface area of the powder of sample 1 measured by nitrogen BET multilayer adsorption method was 5.12m ² ·g ^-1 ; the primary discharge capacity of the prepared Li _x CoO ₂ was 147mAh·g ^-1 .

Claims (1)

1. a kind of reclaims and prepares Li _x CoO from discarded lithium ion battery _The method, x=0.95～1.05 in the formula, it is characterized in that comprising the following steps: (1) Cut the battery in water to separate the positive electrode material from other components, and cut the positive electrode material into small pieces; (2) Soak the cut positive plate fragments in N-methyl-2-pyrrolidone liquid, 1.5-2.0L of N-methyl-2-pyrrolidone is needed for each 1kg of positive electrode fragments, heat the liquid to 85-100°C, After 15 to 30 minutes, the positive electrode active material Li _x CoO ₂ and carbon black adhering to the aluminum foil can fall off into the liquid, take out the aluminum foil, filter, and recover N-methyl-2-pyrrolidone for recycling. Wash the filtered powder, filter and dry to obtain black powder; (3) Disperse the obtained black powder in a nitric acid solution with a mass concentration of 10-30% or a hydrochloric acid solution with a mass concentration of 10-30%. Every 0.1-0.5kg of powder requires 1-1.5L of nitric acid solution or hydrochloric acid solution, and Add dropwise 10～50ml mass concentration of 1～5% hydrogen peroxide solution in this solution, stir for 40 minutes, filter to obtain nitrate solution or chloride solution containing Co ²⁺ , Li ⁺ ions; measure by EDTA titration The concentration of the Co ^ion in the solution is determined, and the concentration of the ^Li ion in the solution is measured by the fluoride ion selective electrode method; (4) At room temperature, slowly add NH ₃ ·H ₂ O to the acidic leaching solution containing Co ²⁺ and Li ⁺ ions prepared in step (3), adjust and control the pH of the solution to 8-11, and form a blue color Precipitation, while adding one of the following surfactants: Polyacrylic acid, polyethylene glycol, polymethacrylic acid or polyethyleneimine, the addition amount is 1-5% of the mass content of the original black powder, and the stirring is continued for 8-12 hours; (5) water bath heating step (4) solution to 80～95 ℃, adjust the concentration of Li ion in the suspension by adding LiOH, and make molar ratio Li ^: Co=(1～1.10): 1; At the same time, in the suspension, dropwise add a concentration of 2 to 5 mol/L NH ₄ HCO ₃ solution, the amount added is to make the molar number of NH ₄ HCO ₃ greater than 1.6 to 2 times the molar number of Li ⁺ in the solution, Keep stirring for 2-4 hours; (6) Filter and dry the precipitate in the suspension in step (5), and calcinate at a temperature of 600-900° C. for 7-12 hours to obtain Li _x CoO ₂ powder.