Method for preparing regenerated lithium-rich manganese-based positive electrode material by taking retired lithium ion battery positive electrode material as raw material

Abstract

The invention discloses a method for preparing a regenerated lithium-rich manganese-based positive electrode material by taking a retired lithium ion battery positive electrode material as a raw material. Comprising the following steps: 1) mixing waste NCM111 positive electrode material powder with an acid solvent to obtain a leaching solution I; mixing the waste LMO positive electrode material powder with an acid solvent to obtain a leaching solution II; measuring the concentrations of nickel ions, cobalt ions and manganese ions in the two lixiviums, adjusting the proportion of the two lixiviums according to the stoichiometric ratio of nickel, cobalt and manganese elements in the lithium-rich manganese, and mixing to obtain a positive electrode material lixivium; the preparation method comprises the following steps of 1) preparing a positive electrode material leachate, 2) dissolving sodium bicarbonate in a mixed solvent of alkali and water to obtain a clear solution, 3) dropwise adding the clear solution into the positive electrode material leachate, heating, stirring, adjusting the pH value to 6.5-11.5, and carrying out suction filtration to obtain a lithium-rich manganese oxide precursor, and 4) mixing the lithium-rich manganese oxide precursor with a lithium source, and carrying out calcination I and calcination II to obtain the regenerated lithium-rich manganese-based positive electrode material.

Description

Technical Field

[0001] The present application relates to a method for preparing a regenerated lithium-rich manganese-based positive electrode material using retired lithium-ion battery positive electrode materials as raw materials, and belongs to the field of waste battery material recycling. Background Art

[0002] Due to its advantages such as high operating voltage, light weight, no memory effect, and long cycle life, lithium-ion battery technology is becoming increasingly mature and is widely used in electronic products such as portable devices and electric vehicles. However, due to its limited service life, a large number of waste lithium-ion batteries are generated. Waste LIBs (lithium-ion batteries) contain toxic heavy metals and organic solvents. If they are treated in unreasonable ways such as incineration or soil landfill, they will pose a certain threat to the environment and human health. But at the same time, strategic cobalt, scarce lithium and other metal resources make waste LIBs a secondary source of many metal elements, and the cost of lithium, cobalt and other elements obtained through recycling will be greatly reduced. Therefore, scientific and effective recycling of waste LIBs can not only effectively solve the pollution to the environment during the treatment process, but also alleviate the problem of resource shortage, which has important economic and environmental significance.

[0003] The recycling and regeneration methods of positive electrode materials can be divided into three types: pyrometallurgy, hydrometallurgy and direct recycling and regeneration. Pyrometallurgy and hydrometallurgy have been restricted by environmental protection and economic costs due to their shortcomings of violent reactions, high energy consumption, high harmful gas emissions, serious pollution and complex processes. The direct regeneration method is to directly regenerate the failed positive electrode material based on its composition and structure. It has a short process and low energy and chemical consumption, so it has lower costs and is more environmentally friendly.

[0004] At present, most of the related recycling work focuses on repairing and regenerating the same ternary cathode material. The process is relatively cumbersome, the investment cost is high, and the recycled raw materials may not meet people's needs in terms of energy density and other properties. Therefore, regenerating into better high-energy-density energy storage materials can become another better option for battery recycling. Summary of the invention

[0005] In this application, NCM111 refers to a ternary positive electrode material in which the ratio of nickel (Ni), cobalt (Co), and manganese (Mn) is 1:1:1, and the chemical formula is LiNi1 / 3Co1 / 3Mn1 / 3O2.

[0006] In this application, LMO positive electrode material refers to lithium manganese oxide positive electrode material, and the chemical formula is LiMn2O4.

[0007] According to one aspect of the present application, there is provided a method for preparing a regenerated lithium-rich manganese-based positive electrode material using a retired lithium-ion battery positive electrode material as a raw material, comprising the following steps: 1) Mix the waste NCM111 cathode material powder with an acidic solvent to obtain leachate I; mix the waste LMO cathode material powder with an acidic solvent to obtain leachate II; determine the nickel ion, cobalt ion and manganese ion concentrations of the two leachates by ICP (inductively coupled plasma spectrometer). 1.2 Mn 0.54 Co 0.13 Ni 0.13 The nickel, cobalt and manganese elements in O2 are adjusted in proportion to the two leaching solutions according to the stoichiometric ratio, and the positive electrode material leaching solution is obtained by mixing; 2) dissolving sodium bicarbonate in a mixed solvent of alkali and water to obtain a clear solution; 3) dropping the clarified solution into the positive electrode material leachate, heating and stirring, adjusting the pH to 6.5-11.5, and filtering to obtain a lithium-rich manganese oxide precursor; 4) The lithium-rich manganese oxide precursor is mixed with a lithium source, calcined I, and calcined II to obtain a regenerated lithium-rich manganese-based positive electrode material.

[0008] 1), the acidic solvent is selected from an organic acid aqueous solution or a hydrogen peroxide aqueous solution.

[0009] The concentration of the organic acid aqueous solution is 1-4 mol / L.

[0010] The organic acid is selected from at least one of acetic acid, citric acid, ascorbic acid, formic acid and oxalic acid.

[0011] The concentration of the hydrogen peroxide aqueous solution is 1-10 vol%.

[0012] The solid-to-liquid ratio of the waste NCM111 positive electrode material powder or the waste LMO positive electrode material powder to the acidic solvent is 5-35 g / L.

[0013] The mixing temperature is 40-90°C.

[0014] The mixing time is 10 to 180 minutes.

[0015] Waste NCM111 positive electrode material powder and waste LMO positive electrode material powder are obtained by soaking, washing, disassembling, crushing, screening and cleaning waste lithium manganese oxide and nickel cobalt manganese ternary lithium-ion battery positive electrode materials.

[0016] 2), the alkali is selected from aqueous ammonia and / or sodium hydroxide solution.

[0017] In the mixed solvent of alkali and water, the volume ratio of alkali to water is 1:1 to 1:5.

[0018] In the clear solution, the concentration of sodium bicarbonate is 1-2.5M.

[0019] 3), the heating temperature is 20-70°C.

[0020] The heating time is 1 to 6 hours.

[0021] After heating, it can also be aged for 0.5~4h.

[0022] 4), the lithium source is selected from at least one of lithium carbonate, lithium nitrate and lithium hydroxide.

[0023] The molar ratio of the lithium-rich manganese oxide precursor to the lithium source is 1:1.05-1.25.

[0024] The temperature of the calcination I is 400-550°C.

[0025] The calcination time is 6 to 10 hours.

[0026] The heating rate of the calcination I is 2-10°C / min.

[0027] The temperature of the calcination II is 700-900°C.

[0028] The calcination time II is 10 to 12 hours.

[0029] The heating rate of the calcination II is 2-10°C / min.

[0030] According to another aspect of the present application, a nickel-cobalt-manganese ternary lithium-ion battery positive electrode material is provided, which is obtained by the above method.

[0031] The beneficial effects of this application include: 1) The present application recycles waste lithium battery ternary positive electrode materials to obtain a solution rich in Ni, Co, Mn, and Li ions, and further undergoes a simple reaction to generate a lithium-ion battery rich lithium manganese-based positive electrode material. The process is simple and the flow is easy. An organic acid and a hydrogen peroxide solution are used as a leaching agent. The leaching agent has a mild effect and little pollution to the environment and human body. The leaching solution can be recycled. In addition, the leaching agent has a high leaching efficiency and a suitable extraction capacity.

[0032] 2) Compared with the existing technology, the nickel, cobalt and manganese transition metal elements required for the material are all provided by the NCM111 and LMO material leaching solution, without the need to add other transition metal salts, which reduces costs and operation steps.

[0033] 3) The provided method has a simple process and a simple procedure, and the type and content of the metal ion source can be adjusted. During the recovery process, the recovered valuable Ni, Co, and Mn ions are all active metals of the positive electrode material, which can effectively provide capacity.

[0034] 4) The method provided, when synthesizing the positive electrode material of lithium-ion batteries, uses the co-precipitation method, which has a mature process and a simple process, and can be effectively recycled and regenerated into a lithium-rich manganese-based positive electrode material for lithium-ion batteries. The prepared positive electrode material therefore has better rate performance and cycle performance, and realizes the recycling of resources to a certain extent. DETAILED DESCRIPTION

[0035] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0036] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0037] Embodiment 1: Waste lithium manganese oxide and nickel-cobalt-manganese ternary lithium-ion batteries are soaked, washed, disassembled, crushed, screened and cleaned to obtain the positive electrode material powder; the positive electrode material powder is mixed with 4 mol / L acetic acid at a solid-liquid ratio of 15 g / L, heated and stirred, the heating temperature is 90°C, the reaction time is 2 h, and the concentrations of nickel ions, cobalt ions and manganese ions in the filtrate are determined by ICP, and the lithium-rich manganese Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 The nickel, cobalt and manganese elements in O2 are adjusted in the stoichiometric ratio to obtain the positive electrode material leachate; Dissolve 1.5M sodium bicarbonate in a mixed solvent of ammonia water and deionized water in a volume ratio of 1:3 to obtain a clear solution, and drop the clear solution into the positive electrode material leachate while heating at 20°C and stirring, adjust the pH to 7.0, stir for 6 hours, age for 1 hour, and filter to obtain a lithium-rich manganese oxide precursor; The lithium-rich manganese oxide precursor is mixed with lithium carbonate in a molar ratio of 1:1.25 and calcined in a muffle furnace. The first stage sintering temperature is 400°C, the sintering time is 6 hours, and the heating rate is 2°C / min; the second stage sintering temperature is 700°C, the sintering time is 10 hours, and the heating rate is 2°C / min, to obtain a regenerated lithium-rich manganese-based positive electrode material.

[0038] Embodiment 2: Waste lithium manganese oxide and nickel-cobalt-manganese ternary lithium-ion batteries are soaked, washed, disassembled, crushed, screened and cleaned to obtain the positive electrode material powder; the positive electrode material powder is mixed with 2 mol / L acetic acid at a solid-liquid ratio of 35 g / L, heated and stirred, the heating temperature is 500°C, the reaction time is 0.5 h, and the concentrations of nickel ions, cobalt ions and manganese ions in the filtrate are determined by ICP, and the lithium-rich manganese Li 1.2 Mn 0.54 Co 0.13 Ni 0.13The nickel, cobalt and manganese elements in O2 are adjusted in the stoichiometric ratio to obtain the positive electrode material leachate; Dissolve 2M sodium bicarbonate in a mixed solvent of ammonia water and deionized water in a volume ratio of 1:3 to obtain a clear solution, and drip the clear solution into the positive electrode material leachate while heating at 60° C. and stirring, adjust the pH to 9.0, stir for 4 hours, age for 2 hours, and filter to obtain a lithium-rich manganese oxide precursor; The lithium-rich manganese oxide precursor is mixed with lithium carbonate in a molar ratio of 1:1.23 and calcined in a muffle furnace. The first stage sintering temperature is 500°C, the sintering time is 10 hours, and the heating rate is 5°C / min; the second stage sintering temperature is 850°C, the sintering time is 12 hours, and the heating rate is 5°C / min, to obtain a regenerated lithium-rich manganese-based positive electrode material.

[0039] Test Example 1 Battery cycle performance test method: The prepared regenerated lithium-rich manganese-based cathode material powder, superconductive carbon, and polyvinylidene fluoride are mixed in a mass ratio of 7:2:1, the slurry is evenly coated, vacuum dried at 80°C for 12 hours, and punched into pole pieces. Lithium sheets are used as counter electrodes, lithium high-voltage electrolytes, and Celgard 2400 diaphragms are assembled into button cells in a glove box filled with argon.

[0040] At a constant temperature of 25°C, the Xinwei battery testing system was used with a voltage range of 2.0-4.8V, a current density of 1C(), and constant current charge and discharge to test its electrochemical cycle stability performance.

[0041] And under the temperature and voltage range conditions of the above cycle test, the 0.1C, 0.2C, 0.5C, 1C, 2C, and 5C rate performances were tested.

[0042] Test results and conclusions: The initial capacity of the regenerated lithium-rich manganese-based cathode material at 1C is 183.12 mAh g-1, which is slightly lower than the normal lithium-rich manganese material (194.82 mAh g-1). However, after 500 cycles, the capacity of R-LMR is 132.678 mAh g-1, still with a high capacity retention rate of 72.45%, while the control sample only has a capacity of 85.85 mAh g-1, and the capacity retention rate is as low as less than 50% (44.07%). The rate performance of various cathode materials was experimented in the increasing current rate range of 0.1-10 C. At high rates of 2, 5, 8 and 10C, the discharge specific capacity is 162.3, 90.49 and 79.88 mAh g-1, respectively. When the current returns to 0.1 C, the regenerated lithium-rich manganese-based cathode material can still recover a large amount of capacity.

[0043] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a regenerated lithium-rich manganese-based positive electrode material using retired lithium-ion battery positive electrode materials as raw materials, characterized in that: The following steps are involved: 1) Mix the waste NCM111 cathode material powder with an acidic solvent to obtain leachate I; mix the waste LMO cathode material powder with an acidic solvent to obtain leachate II; determine the concentrations of nickel ions, cobalt ions and manganese ions in the two leachates, and 1.2 Mn 0.54 Co 0.13 Ni 0.13 The nickel, cobalt and manganese elements in O2 are adjusted in proportion to the two leaching solutions according to the stoichiometric ratio, and the positive electrode material leaching solution is obtained by mixing; 2) dissolving sodium bicarbonate in a mixed solvent of alkali and water to obtain a clear solution; 3) dropping the clarified solution into the positive electrode material leachate, heating and stirring, adjusting the pH to 6.5-11.5, and filtering to obtain a lithium-rich manganese oxide precursor; 4) The lithium-rich manganese oxide precursor is mixed with a lithium source, calcined I, and calcined II to obtain a regenerated lithium-rich manganese-based positive electrode material.

2. The method according to claim 1, characterized in that 1), the acidic solvent is selected from an organic acid aqueous solution or a hydrogen peroxide aqueous solution; The concentration of the organic acid aqueous solution is 1-4 mol / L; The organic acid is selected from at least one of acetic acid, citric acid, ascorbic acid, formic acid and oxalic acid.

3. The method according to claim 2, characterized in that 1), the concentration of the hydrogen peroxide aqueous solution is 1-10 vol%; The solid-to-liquid ratio of the waste NCM111 positive electrode material powder or the waste LMO positive electrode material powder to the acidic solvent is 5-35 g / L.

4. The method according to claim 1, characterized in that: 1), the mixing temperature is 40-90°C; The mixing time is 10 to 180 minutes.

5. The method according to claim 1, characterized in that 2), the base is selected from aqueous ammonia and / or sodium hydroxide solution; In the mixed solvent of alkali and water, the volume ratio of alkali to water is 1:1 to 1:5; In the clear solution, the concentration of sodium bicarbonate is 1-2.5M.

6. The method according to claim 1, characterized in that 3), the heating temperature is 20-70°C; The heating time is 1 to 6 hours.

7. The method according to claim 1, characterized in that 4), wherein the lithium source is selected from at least one of lithium carbonate, lithium nitrate and lithium hydroxide; The molar ratio of the lithium-rich manganese oxide precursor to the lithium source is 1:1.05-1.

25.

8. The method according to claim 1, characterized in that 4), the temperature of calcining I is 400-550°C; The calcination time is 6 to 10 hours; The heating rate of the calcination I is 2-10°C / min.

9. The method according to claim 1, characterized in that: 4), the temperature of calcination II is 700-900°C; The calcination time of II is 10 to 12 hours; The heating rate of the calcination II is 2-10°C / min.

10. A nickel-cobalt-manganese ternary lithium-ion battery positive electrode material, characterized in that: Obtained by the method according to any one of claims 1 to 9.