CN115275415A - Method for recovering lithium from retired lithium battery and regenerating positive electrode material - Google Patents

Method for recovering lithium from retired lithium battery and regenerating positive electrode material Download PDF

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CN115275415A
CN115275415A CN202210937394.8A CN202210937394A CN115275415A CN 115275415 A CN115275415 A CN 115275415A CN 202210937394 A CN202210937394 A CN 202210937394A CN 115275415 A CN115275415 A CN 115275415A
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lithium
manganese
leaching
cobalt
nickel
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胡敬平
汤建建
梁智霖
武龙胜
刘露
杨小容
邓浩
徐倩
侯慧杰
杨家宽
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Huazhong University of Science and Technology
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/54—Reclaiming serviceable parts of waste accumulators
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00—Lithium compounds
    • C01D15/08—Carbonates; Bicarbonates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/84—Recycling of batteries or fuel cells

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Abstract

The invention belongs to the technical field of retired lithium ion battery recovery, and particularly relates to a method for recovering lithium from retired lithium batteries and regenerating a positive electrode material. Divalent manganese ions are used as a leaching agent of lithium in the anode material, and the divalent manganese ions are easily hydrolyzed in the hydrothermal process to generate oxidation reaction to generate solid MnO 2 Transferring electrons to the positive electrode material to induce cobalt, manganese and other transition metals to perform a reduction reaction and release lithium into the solution, and leaving the added manganese and the transition metals of the positive electrode material in leached solid residues, so that the lithium is efficiently and selectively leached;the lithium-rich leaching solution can be prepared into lithium carbonate for recycling; the leaching residues become loose and porous due to the leaching of a large amount of lithium, and the materials used as raw materials are uniformly reacted in the short-flow regeneration process, so that the regenerated anode material has a better structure and electrochemical properties. The invention has simple regeneration and recovery flow, no impurity introduced in the process, good product quality and great application prospect.

Description

Method for recovering lithium from retired lithium battery and regenerating positive electrode material
Technical Field
The invention belongs to the technical field of retired lithium ion battery recovery, and particularly relates to a method for recovering lithium from retired lithium batteries and regenerating a lithium anode material; more particularly, relates to a method for recycling lithium from a lithium ion battery cathode material and regenerating a nickel cobalt lithium manganate cathode material in a short process.
Background
The lithium ion battery is widely used in the global range by virtue of the advantages of larger specific capacity, higher energy density, longer service life and the like. From electronic devices such as smart phones and notebook computers to new energy automobiles, the demand of lithium ion batteries is rapidly increasing, and the rapid development of the human society is not away from the promotion of the lithium ion batteries.
Along with the increase of the usage amount of the lithium ion batteries, the waste amount is increased day by day, if the retired batteries are discarded without treatment, a plurality of heavy metals and electrolyte contained in the retired batteries are directly discharged into the environment, so that great harm is caused to the ecological environment and the human health, and huge resource waste is caused. At present, only less than 5 percent of the retired lithium ion batteries are properly recycled globally, and the effective method technology is adopted to recycle and regenerate the retired lithium ion batteries, particularly the positive electrode materials rich in heavy metals, which is the necessary requirement for environmental protection and sustainable development of resources.
The existing regeneration and recovery method of the retired lithium ion battery anode material is mainly a hydrometallurgy process, a large amount of strong acid such as hydrochloric acid and sulfuric acid is used as a leaching agent, expensive and dangerous hydrogen peroxide is used as a reducing agent, all metals in the anode material are leached to obtain a leaching solution containing lithium, nickel, cobalt and manganese elements, then various metals are separated and recovered through steps of extraction by an extracting agent, pH regulation, precipitation and the like, and finally the anode material is prepared through regeneration. The method preferentially recovers valuable metals such as nickel, cobalt, manganese and the like, and lithium is usually separated out as a byproduct or is enriched in waste residues, so that the recovery value of the lithium is weakened, and meanwhile, a large amount of reagents and energy are consumed for extracting and separating metal ions in the leachate, thereby seriously hindering the industrial application of the recovery and regeneration of the anode material of the retired lithium ion battery.
Some existing selective lithium leaching processes focus on pyrometallurgy, concentrated sulfuric acid is usually used as a roasting agent to treat waste anode materials at a high temperature of over 800 ℃, so that the energy consumption is high, secondary pollution is easy to generate, the leaching rate of lithium is not high, valuable metals such as nickel, cobalt, manganese and the like need to be leached and separated subsequently by combining a hydrometallurgy technology, and the materials can be used for regenerating anode materials, and the process flow is complex.
In the prior art, the lithium ion anode material is regenerated after valuable recovery is carried out on the retired lithium ion battery anode material, because a leaching agent used in the recovery process is complex, the obtained product has more impurities, and the performance of the regenerated anode material obtained after the recovered product is regenerated is generally poor. In addition, some methods obtain metal salt products by performing complicated separation and purification steps on leachate, and then regenerate the positive electrode material by using a solid-phase sintering method, so that the cost is high, the requirements on the calcination temperature and the calcination time in the regeneration and sintering process are high, higher calcination temperature and longer calcination time are often required, and the energy consumption is high. How to recover lithium from the anode material of the retired lithium ion battery and regenerate the nickel cobalt lithium manganate anode material with better electrochemical performance in a short process is a technical problem which needs to be solved urgently at present.
Disclosure of Invention
The invention provides a method for efficiently recovering lithium and simultaneously regenerating a cathode material in a short-process green way, aiming at the problems of low lithium selective leaching rate, high energy consumption, serious secondary pollution, complex process flow and the like of the cathode material of an retired lithium ion battery in the prior art, and the defects that the leached metal can be used for regenerating and preparing the cathode material after being separated and purified. The bivalent manganese ions in the aqueous solution have lower oxidation-reduction potential and can be converted into oxides with high valence states, and the characteristic that the bivalent manganese ions are easy to hydrolyze is the bivalent manganese ions. The invention utilizes bivalent manganese ions as a leaching agent of the anode material lithium, and the bivalent manganese ions undergo an oxidation reaction under the self-hydrolysis action in the hydrothermal process to generate solid MnO 2 Transferring electrons to the positive electrode material to induce cobalt, manganese and other transition metals to perform a reduction reaction so as to release lithium into the solution, and leaving the added manganese and the transition metals of the positive electrode material in the solid leaching residue, so that the lithium is efficiently and selectively leached; the lithium-rich leaching solution can be prepared into lithium carbonate for recycling; the leaching residues are loose and porous due to the leaching of a large amount of lithium, which is beneficial to full reaction and structural rearrangement in the regeneration process, and can be directly used as a raw material to be regenerated and prepared into the nickel cobalt lithium manganate positive electrode material with good physical property and electrochemical property, thereby solving the technical problems of difficult lithium ion recovery from the retired battery, low leaching rate and leaching selectivity, poor electrochemical property of the regenerated positive electrode material and the like in the prior art.
In order to achieve the above object, the present invention provides a method for recovering lithium from a retired lithium battery, comprising the steps of:
(1) Sequentially pretreating retired lithium batteries to obtain waste positive electrode materials;
(2) Mixing the waste anode material obtained in the step (1) with an aqueous solution of divalent manganese ions, and sealing the mixtureHydrothermal reaction is carried out, and the divalent manganese ions are oxidized to generate MnO 2 Transferring electrons to the waste anode material to induce the transition metal in the waste anode material to perform a reduction reaction and release lithium ions into the solution, performing solid-liquid separation after the reaction is finished to obtain a leaching solution and leaching residues, wherein the leaching solution is a lithium-rich solution, and the leaching residues contain MnO generated by the reaction 2 And transition metals in the waste positive electrode material;
(3) And (3) adding carbonate into the lithium-rich solution obtained in the step (2) to perform a precipitation reaction, thereby obtaining a lithium carbonate product.
Preferably, the main component of the waste positive electrode material in the step (1) is at least one of lithium nickel cobalt manganese oxide, lithium manganate, lithium cobaltate and lithium nickelate.
Preferably, the aqueous solution of divalent manganese ions in the step (2) is at least one of a manganese acetate solution, a manganese oxalate solution, a manganese chloride solution, a manganese sulfate solution and a manganese nitrate solution, and is more preferably a manganese acetate solution.
Preferably, the molar ratio of the divalent manganese ions to the lithium ions in the waste cathode material in the step (2) is (0.25-1): 1; the solid-liquid ratio of the waste anode material to the aqueous solution of the divalent manganese ions is 25-200 g/L.
Preferably, the hydrothermal reaction in the step (2) has a reaction temperature of 100-220 ℃ and a reaction time of 1-28 h.
Preferably, the carbonate in step (3) is at least one of sodium carbonate, ammonium carbonate and potassium carbonate.
In another aspect, the invention also provides a method for regenerating a nickel-cobalt-manganese cathode material by using the leaching residue and the lithium carbonate product obtained in the method for recovering lithium, which comprises the following steps:
s1: uniformly mixing the leaching residue and lithium carbonate, and measuring the content of each metal element;
s2: according to the proportion requirement of each element in the regenerated anode material, adding a proper amount of lithium salt, nickel salt, cobalt salt and manganese salt, and uniformly mixing;
s3: and (3) calcining the uniformly mixed mixture obtained in the step (S2) in an air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
Preferably, the ratio of lithium, nickel, cobalt and manganese elements in the regenerated cathode material in step S2 is 1.05:0.3:0.3:0.3, 1.05:0.8:0.1:0.1 or 1.05:0.5:0.2:0.3;
the lithium salt in the step S2 is at least one or a combination of lithium carbonate, lithium hydroxide, lithium acetate and lithium nitrate; the nickel salt is at least one or a plurality of combinations of nickel acetate, nickel sulfate and nickel nitrate, and the cobalt salt is at least one or a plurality of combinations of cobalt acetate, cobalt sulfate and cobalt nitrate; the manganese salt is at least one or a combination of manganese acetate, manganese sulfate and manganese nitrate.
Preferably, step S3 comprises the following sub-steps:
s301: pre-calcining the mixture uniformly mixed in the step S2 in an air atmosphere to preliminarily form the mixture;
s302: grinding the preliminarily formed product, and then calcining for the second time in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
Preferably, the calcination temperature of the pre-calcination is 400-600 ℃, and the pre-calcination time is 3-7 h; the second calcination has the calcination temperature of 750-950 ℃ and the calcination time of 8-12 h.
Generally, compared with the prior art, the technical scheme of the invention has the following beneficial effects:
(1) The method for recovering lithium from the retired battery uses bivalent manganese ions as active substances, and bivalent manganese ions in an aqueous solution have lower oxidation-reduction potential and can be converted into oxides with high valence, and oxidation reaction is carried out to generate MnO by utilizing the characteristic that the bivalent manganese ions are easy to hydrolyze in the hydrothermal process 2 Solid and electrons are transferred to the anode material to induce the valence state change of transition metals such as cobalt, manganese and the like in the anode material to generate reduction reaction and release lithium ions into the solution, and the added transition metals of manganese and the anode material are still left in solid leaching residues, so that the efficient and selective lithium leaching is realized, and the condition that a large amount of high-concentration strong acid is used for hydrometallurgically separating and recovering step by step is avoidedSecondary pollution and energy consumption caused by lithium and a high-temperature pyrometallurgical selective lithium leaching process. Different from the generally-thought principle of lithium recovery based on ion exchange in the prior art, the invention firstly provides a new theory that bivalent manganese ions in an aqueous solution have lower oxidation-reduction potential and can be converted into oxides with high valence state through hydrolysis reaction, so that the electron-induced anode material transition metal is spontaneously subjected to valence state regulation to selectively leach lithium. The invention has the advantages that the leaching rate of the lithium of the anode material reaches more than 91 percent under better conditions, and the leaching selectivity reaches 100 percent. The lithium carbonate prepared by recovering the lithium-rich leaching solution can be used for preparing a regenerated positive electrode material and can also be widely used in the fields of chemical industry, metallurgy, petroleum and the like.
(2) According to the method, firstly, the decommissioned batteries are subjected to full pretreatment by means of disassembling, crushing, alkali treatment for removing aluminum foil, calcination for removing a binder and the like, then divalent manganese ions are adopted to leach lithium ions in the waste cathode material under a hydrothermal condition, residues after lithium leaching and recycled lithium carbonate are efficiently selected as raw materials to directly regenerate the nickel-cobalt lithium manganate cathode material, all steps are cooperatively matched, and the method is absent, so that short-flow green regeneration of the waste cathode material is realized, the separation and purification processes of lithium, nickel, cobalt and manganese elements are omitted, the process flow is simple, and the consumption of reagents and energy is low.
(3) According to the invention, lithium selective leaching and short-process regeneration of the cathode material are organically combined, the lithium leaching efficiency determines the loosening degree of the particle structure of the leaching residue, and the loosening degree of the particles of the leaching residue can obviously influence the physical property and electrochemical performance of the regenerated cathode material. After the nickel-cobalt-manganese ternary positive electrode material obtained by regeneration in the preferred embodiment of the invention is assembled into a battery, the cyclic charge and discharge performance of the nickel-cobalt-manganese ternary positive electrode material under the multiplying power of 0.5C (1C= 230mAh/g) is measured, the initial discharge specific capacity is 117.2mAh/g, and the capacity retention rate is 82.0% after 100 times of charge and discharge. The method realizes the high-selectivity leaching of the waste cathode material lithium and the regeneration of the nickel cobalt lithium manganate cathode material with good electrochemical performance, and achieves the full absorption and full substance recycling of the cathode material of the retired lithium ion battery.
(4) The method adopts a wet hydrothermal leaching method, has a wide working temperature range, is applicable to a divalent manganese ion leaching agent which is cheap and easy to obtain and has a plurality of types, and can realize selective recovery of lithium and short-process regeneration of the nickel cobalt lithium manganate cathode material at low cost and low energy consumption.
(5) The short-process regeneration method for the lithium recovery and nickel cobalt lithium manganate cathode material, provided by the invention, has the advantages of wide application range, simplicity and convenience in operation, no secondary pollution, low cost, good product quality, high economic value and good popularization prospect, and has considerable potential in the field of recovery and regeneration of retired lithium ion batteries.
Drawings
Fig. 1 is a flow chart of a method for recovering lithium from a retired lithium battery and regenerating a positive electrode material according to the present invention.
FIG. 2 is an X-ray diffraction (XRD) pattern of the hot-dipped residue of example 1.
FIG. 3 is a high resolution X-ray photoelectron spectroscopy (XPS) chart of Co and Mn in example 1.
Fig. 4 is an X-ray diffraction (XRD) pattern of lithium carbonate recovered in example 1.
FIG. 5 is an X-ray diffraction (XRD) pattern of the regenerated lithium nickel cobalt manganese oxide positive electrode material of example 1.
FIG. 6 is a graph showing the leaching rate of Li-Ni-Co under different conditions in examples 1 to 5 and comparative examples 1 to 2.
Fig. 7 is a Scanning Electron Microscope (SEM) image of the leaching residue of the out-of-service lithium ion battery positive electrode material under different conditions (example 1 and comparative examples 3 to 5).
Fig. 8 is a graph comparing the specific discharge capacity of the regenerated lithium nickel cobalt manganese oxide positive electrode material of example 1 and comparative examples 3 to 5 under different conditions, which is cycled for 100 times at a rate of 0.5C.
Fig. 9 is a graph comparing the lithium leaching effects of example 1 and comparative example 6 in hydrothermal and ball milling processes, respectively.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention provides a method for recovering lithium from a retired lithium battery, which comprises the following steps:
(1) Pretreating the retired lithium battery to obtain a waste positive electrode material;
(2) Mixing the waste positive electrode material obtained in the step (1) with an aqueous solution of divalent manganese ions, and carrying out hydrothermal reaction under a closed condition, wherein the divalent manganese ions are subjected to oxidation reaction at high temperature and high pressure to generate MnO 2 Transferring electrons to the waste anode material to induce the transition metal in the waste anode material to perform a reduction reaction and release lithium ions into the solution, performing solid-liquid separation after the reaction is finished to obtain a leaching solution and leaching residues, wherein the leaching solution is a lithium-rich solution, and the leaching residues contain MnO generated by the reaction 2 And transition metals in the waste cathode material;
(3) And (3) adding carbonate into the lithium-rich solution obtained in the step (2) to perform a precipitation reaction, thereby obtaining a lithium carbonate product.
The recycling method can be suitable for various retired lithium batteries, and in some embodiments, the main component of the waste cathode material in the step (1) is at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide and lithium nickel oxide.
The pretreatment comprises the steps of discharging, disassembling and removing part or all other components except the lithium battery anode material, and can be manual disassembly pretreatment or integrated industrial equipment pretreatment, and the manual disassembly pretreatment generally comprises the steps of manual disassembly, crushing, alkali treatment for removing aluminum foil and calcination for removing a binder; the pretreatment of the integrated industrial equipment generally comprises the steps of mechanical crushing, magnetic separation, air separation and calcination.
In some embodiments, the disassembling in the manual pretreatment is specifically: connecting the retired battery to a saturated NaCl solution for discharging for 12-24h, manually cutting off a battery shell after discharging, taking down a positive electrode tab and a negative electrode tab, and then separately collecting a positive electrode plate, a negative electrode plate and a diaphragm. The crushing is as follows: the positive plate containing the aluminum foil is cut into fragments (such as about 2cm multiplied by 2 cm) by using scissors, or the positive plate is ball-milled for 0.5 to 3 hours at the rotating speed of 200 to 500r/min by using a ball mill, so that the fragments can be obtained. The aluminum foil removal by alkali treatment specifically comprises the following steps: and (3) mixing the crushed positive plate with NaOH or KOH according to the mass ratio of 1:0.1-1:1 adding a proper amount of water, mixing and stirring until bubbles are not generated in the reaction solution, indicating that the aluminum foil is basically dissolved, filtering the solution, cleaning and filtering for many times by using ultrapure water, and drying the obtained black solid powder in a 60 ℃ drying oven. The step of removing the binder by calcination comprises the following specific steps: calcining the black solid powder at 550-700 ℃ for 3-5h to remove the binder; finally, the waste anode material is obtained.
In other embodiments, the waste cathode material is obtained by comprehensive physical separation of large-scale production through equipment such as mechanical crushing, air separation, magnetic separation and the like. The method specifically comprises the following steps: discharging the retired battery in a saturated NaCl solution for 12-24h, putting the retired battery into lithium battery crushing and sorting integrated equipment after discharging, separating the battery into a mixture containing a positive electrode material, negative electrode graphite, an iron sheet, an aluminum foil and a copper foil through a coarse crushing and sorting device, separating the iron sheet through a magnetic separation device in sequence, separating nonmetal materials such as the negative electrode graphite through an air separation device, separating the copper and the aluminum through a heating device to obtain black solid powder, and calcining the black solid powder in a muffle furnace at the temperature of 550-700 ℃ for 3-5h to obtain the waste ternary positive electrode material.
In some embodiments, the aqueous solution of divalent manganese ions in step (2) is at least one of a manganese acetate solution, a manganese oxalate solution, a manganese chloride solution, a manganese sulfate solution and a manganese nitrate solution, preferably a manganese acetate solution.
In some embodiments, the molar ratio of the divalent manganese ions to the lithium ions in the waste cathode material in step (2) is (0.25-1): 1; the solid-liquid ratio of the waste anode material to the aqueous solution of the divalent manganese ions is 25-200 g/L.
In some embodiments, the hydrothermal reaction in step (2) is performed at a reaction temperature of 100 to 220 ℃ for 1 to 28 hours, preferably at a reaction temperature of 160 to 200 ℃ for 12 to 24 hours.
In some embodiments, the carbonate in step (3) is at least one of sodium carbonate, ammonium carbonate, and potassium carbonate.
In some embodiments, in the step (3), the lithium-rich solution obtained by the reaction in the step (2) is concentrated, carbonate is added to react at 90-98 ℃ for 1-3h to obtain white solid, and the white solid is filtered and washed for 2-4 times by using boiling water and dried to obtain lithium carbonate.
The invention also provides a method for regenerating a nickel-cobalt-manganese ternary cathode material by using the leaching residue and the lithium carbonate product obtained in the method for recovering lithium, which comprises the following steps:
s1: uniformly mixing the leaching residue and lithium carbonate, and measuring the content of each metal element;
s2: according to the proportion requirement of each element in the regenerated anode material, adding a proper amount of lithium salt, nickel salt, cobalt salt and manganese salt, and uniformly mixing;
s3: and (3) calcining the uniformly mixed mixture obtained in the step (S2) in an air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
In some embodiments, the ratio of lithium, nickel, cobalt, and manganese in the regenerated cathode material in step S2 is 1.05:0.3:0.3:0.3, 1.05:0.8:0.1:0.1 or 1.05:0.5:0.2:0.3.
in some embodiments, the lithium salt in step S2 is at least one or more of lithium carbonate, lithium hydroxide, lithium acetate, and lithium nitrate, the nickel salt is at least one or more of nickel acetate, nickel sulfate, and nickel nitrate, the cobalt salt is at least one or more of cobalt acetate, cobalt sulfate, and cobalt nitrate, and the manganese salt is at least one or more of manganese acetate, manganese sulfate, and manganese nitrate.
In some embodiments, step S3 comprises the sub-steps of:
s301: pre-calcining the mixture uniformly mixed in the step S2 in an air atmosphere to preliminarily form the mixture;
s302: grinding the preliminarily formed product, and then calcining for the second time in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
In some embodiments, the pre-calcination is performed at a calcination temperature of 400 to 600 ℃ for 3 to 7 hours; the second calcination has the calcination temperature of 750-950 ℃ and the calcination time of 8-12 h.
The method uniformly mixes the recovered lithium carbonate and the hydrothermal reaction leaching residue, supplements corresponding metals according to a certain proportion, and directly prepares a brand new anode material by short-process regeneration. According to the invention, divalent manganese ions are used as active substances for selective leaching of lithium, the divalent manganese ions completely participate in reaction and enter residues under better conditions, the leaching rate of the lithium of the cathode material reaches more than 91%, the leaching selectivity reaches 100%, and meanwhile, the residues are loose due to large amount of lithium leaching, and the substances are uniformly reacted in a short-flow regeneration process as raw materials, so that the regenerated cathode material has better structure and electrochemical properties. The invention has simple regeneration and recovery flow, no impurity introduced in the process, good product quality and great application prospect.
The following are examples:
example 1
In this embodiment, a method for selectively leaching lithium from a waste cathode material by using a divalent manganese ion hydrothermal method and regenerating a lithium nickel cobalt manganese oxide cathode material in a short process is shown in fig. 1, and includes the following steps:
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, manually disassembling and separating out the positive plate, shearing the positive plate into fragments of about 2cm multiplied by 2cm, wherein the mass ratio of the fragments to the fragments is 1: adding 0.2 of NaOH into water, stirring until no bubbles are generated, washing, filtering, drying to obtain black solid powder, and finally, placing the black solid powder in a muffle furnace to treat for 3 hours at 650 ℃ to obtain the waste ternary cathode material.
(2) Dissolving 0.2521g of tetrahydrate manganese acetate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery anode material, placing the lithium ion battery anode material and manganese acetate solution in a reaction kettle at 200 ℃ for hydrothermal reaction for 24 hours, and filtering to obtain leachate and leaching residues.
(3) ICP-OES is used for measuring that the leaching rate of lithium in the anode material is 91.78%, the leaching rate of nickel is 0%, the leaching rate of cobalt is 0%, and the leaching selectivity of lithium reaches 100%. Manganese ions can not be detected in the leaching solution, so the lithium-rich leaching solution can be recycled to prepare lithium carbonate.
(4) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture with a molar ratio of lithium, nickel, cobalt and manganese of 1.31:0.45:0.42:1, adding 0.1484g of lithium acetate, 0.1711g of nickel acetate tetrahydrate and 0.1761g of cobalt acetate tetrahydrate to make them meet the weight ratio of 1.05:0.33:0.33:0.33 mole ratio.
(5) And uniformly mixing the mixture, pre-calcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining the pre-calcined product for 10 hours at 850 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
(6) A lithium sheet is used as a negative electrode, a button half-cell is assembled by a regenerated positive electrode material, the cyclic charge and discharge performance of the button half-cell under the multiplying power of 0.5C (1C = 230mAh/g) is measured by using a cell testing system, the initial discharge specific capacity is 117.2mAh/g, and the capacity retention rate is 82.0% after 100 times of charge and discharge.
Fig. 2 is an XRD pattern of solid residue after hydrothermally selective leaching of lithium using divalent manganese ions as an active material in example 1. As can be seen from the figure, mnO was the main component of the leaching residue 2 、Mn 2 NiO 4 、CoMn 2 O 4 Wherein MnO is 2 From the product of the active material after oxidation of divalent manganese ions, mn 2 NiO 4 、CoMn 2 O 4 The composite metal oxides are main components of the anode material after lithium is selectively leached, and Co in the composite metal oxides is +2 valent and Mn in the composite metal oxides is +3 valent.
Fig. 3 shows XPS high resolution spectra of cobalt and manganese elements in the solid residue after hydrothermal selective lithium leaching using a divalent manganese ion as an active material in example 1. It can be known from the figure that the valence states of the elements Co and Mn in the initial waste anode material are +3 and +4, respectively, and the valence states of the elements Co and Mn in the leaching residue are +2 and +3, respectively, which is consistent with the XRD spectrum analysis result, and indicates that the valence states of the transition metals such as cobalt, manganese, etc. in the anode material are reduced. This is probably because the active divalent manganese ions are oxidized to MnO due to hydrolysis reaction in the hydrothermal process because of their low redox potential 2 Providing electrons to the system as positive electrode materialThe electron acceptor receives electrons, induces transition metals such as cobalt and manganese in the anode material to be reduced and reduce the valence state, and releases lithium into the solution.
Fig. 4 is an XRD spectrum of lithium carbonate recovered in example 1, which shows that the recovered lithium carbonate substantially matches standard card 01-080-1307, indicating that the recovered lithium carbonate is of better quality. Fig. 5 is an XRD of the regenerated nickel cobalt lithium manganate ternary cathode material of example 1, in which characteristic peaks of the regenerated cathode material are significant, diffraction peaks (006), (102), (108) and (110) are split clearly, and are completely consistent with standard substance cards 96-400-2444, which shows that the regenerated cathode material of example 1 has high purity and excellent layered structure.
Example 2
The embodiment of the invention provides a method for selectively leaching waste cathode material lithium by utilizing a divalent manganese ion hydrothermal method and regenerating a nickel cobalt lithium manganate cathode material in a short process, which comprises the following steps:
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, manually disassembling and separating out the positive plate, shearing the positive plate into fragments of about 2cm multiplied by 2cm, wherein the mass ratio of the fragments to the fragments is 1: adding 0.2 of NaOH into water, stirring until no bubbles are generated, washing, filtering, drying to obtain black solid powder, and finally, placing the black solid powder in a muffle furnace to treat for 3 hours at 650 ℃ to obtain the waste ternary cathode material.
(2) Dissolving 0.2521g of tetrahydrate manganese acetate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery anode material, placing the lithium ion battery anode material and manganese acetate solution in a reaction kettle at 160 ℃ for hydrothermal reaction for 12 hours, and filtering to obtain leachate and leaching residue.
(3) The leaching rate of lithium in the positive electrode material is 83.81 percent, the leaching rate of nickel is 1.22 percent, the leaching rate of cobalt is 0.24 percent and the leaching selectivity of lithium reaches 98.29 percent by ICP-OES. And recovering the lithium-rich leaching solution to prepare lithium carbonate.
(4) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture with a molar ratio of lithium, nickel, cobalt and manganese elements of 1.25:0.43:0.41:1, 0.1532g of lithium acetate, 0.1769g of nickel acetate tetrahydrate and 0.1804g of cobalt acetate tetrahydrate are added to meet the weight ratio of 1.05:0.33:0.33:0.33 mole ratio.
(5) And uniformly mixing the mixture, pre-calcining for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining for 10 hours at 950 ℃ in the air atmosphere to obtain the regenerated lithium nickel cobalt manganese oxide cathode material.
Example 3
The embodiment of the invention provides a method for selectively leaching waste lithium cathode material and regenerating a lithium nickel cobalt manganese oxide cathode material in a short process by utilizing a divalent manganese ion hydrothermal method, which comprises the following steps:
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, manually disassembling and separating out the positive plate, shearing the positive plate into fragments of about 2cm multiplied by 2cm, and mixing the fragments with NaOH according to the mass ratio of 1:0.2, adding water, stirring until no bubbles are generated, washing, filtering, drying to obtain black solid powder, and finally, placing the black solid powder in a muffle furnace to treat for 3 hours at 650 ℃ to obtain the waste ternary cathode material.
(2) Dissolving 0.2036g of tetrahydrate manganese chloride in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery anode material, placing the cathode material and a manganese acetate solution at a solid-to-liquid ratio of 75g/L in a reaction kettle, carrying out hydrothermal reaction for 12 hours at 160 ℃, and filtering to obtain a leaching solution and leaching residues.
(3) The leaching rate of lithium in the positive electrode material is measured to be 78.92 percent by ICP-OES, the leaching rate of nickel is measured to be 2.12 percent, the leaching rate of cobalt is measured to be 0.38 percent, and the leaching selectivity of lithium reaches 96.93 percent. And recovering the lithium-rich leaching solution to prepare lithium carbonate.
(4) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture with a molar ratio of lithium, nickel, cobalt and manganese elements of 1.41:0.46:0.47:1, 0.1403g of lithium acetate, 0.1676g of nickel acetate tetrahydrate, 0.1621g of cobalt acetate tetrahydrate are added to make it conform to a 1.05:0.33:0.33:0.33 mole ratio.
(5) And uniformly mixing the mixture, pre-calcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining the pre-calcined product for 10 hours at 950 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
Example 4
The embodiment of the invention provides a method for selectively leaching waste cathode material lithium by utilizing a divalent manganese ion hydrothermal method and regenerating a nickel cobalt lithium manganate cathode material in a short process, which comprises the following steps:
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, manually disassembling and separating out the positive plate, cutting the positive plate into fragments of about 2cm multiplied by 2cm, and mixing with NaOH according to a mass ratio of 1:0.2, adding water, stirring until no bubbles are generated, washing, filtering, drying to obtain black solid powder, and finally, placing the black solid powder in a muffle furnace to treat for 3 hours at 650 ℃ to obtain the waste ternary cathode material.
(2) Dissolving 0.1738g of manganese sulfate monohydrate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery anode material, wherein the solid-to-liquid ratio of the anode material to a manganese acetate solution is 75g/L, placing the mixture into a reaction kettle, carrying out hydrothermal reaction at 160 ℃ for 12 hours, and filtering to obtain a leaching solution and leaching residues.
(3) The leaching rate of lithium of the anode material is 74.94 percent, the leaching rate of nickel is 1.06 percent, the leaching rate of cobalt is 1.21 percent and the leaching selectivity of lithium reaches 97.06 percent by ICP-OES. And recovering the lithium-rich leaching solution to prepare lithium carbonate.
(4) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture of lithium, nickel, cobalt and manganese elements with a molar ratio of 1.33:0.42:0.40:1, 0.1468g of lithium acetate, 0.1792g of nickel acetate tetrahydrate, 0.1813g of cobalt acetate tetrahydrate are added to make it meet the conditions of 1.05:0.33:0.33:0.33 molar ratio.
(5) And uniformly mixing the mixture, pre-calcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining the pre-calcined product for 10 hours at 950 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
Example 5
The embodiment of the invention provides a method for selectively leaching waste lithium cathode material and regenerating a lithium nickel cobalt manganese oxide cathode material in a short process by utilizing a divalent manganese ion hydrothermal method, which comprises the following steps:
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, manually disassembling and separating out the positive plate, shearing the positive plate into fragments of about 2cm multiplied by 2cm, and mixing the fragments with NaOH according to the mass ratio of 1:0.2, adding water, stirring until no bubbles are generated, washing, filtering, drying to obtain black solid powder, and finally placing the black solid powder in a muffle furnace to treat for 3 hours at 650 ℃ to obtain the waste ternary cathode material.
(2) Dissolving 0.24mL of 50% manganese nitrate solution in 2.43mL of ultrapure water, adding 0.2g of retired lithium ion battery anode material, wherein the solid-to-liquid ratio of the anode material to manganese acetate solution is 75g/L, placing the mixture in a reaction kettle for hydrothermal reaction at 160 ℃ for 12 hours, and filtering to obtain leachate and leaching residues.
(3) The leaching rate of lithium in the positive electrode material is 77.90%, the leaching rate of nickel is 7.02%, the leaching rate of cobalt is 0.96% and the leaching selectivity of lithium reaches 90.71% by ICP-OES. And recovering the lithium-rich leaching solution to prepare lithium carbonate.
(4) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture with a molar ratio of lithium, nickel, cobalt and manganese elements of 1.47:0.46:0.44:1, 0.1355g of lithium acetate, 0.1677g of nickel acetate tetrahydrate and 0.1713g of cobalt acetate tetrahydrate were added to match the weight ratio of 1.05:0.33:0.33:0.33 mole ratio.
(5) And uniformly mixing the mixture, pre-calcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining the pre-calcined product for 10 hours at 950 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
Example 6
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, manually disassembling and separating out the positive plate, shearing the positive plate into fragments of about 2cm multiplied by 2cm, and mixing the fragments with NaOH according to the mass ratio of 1:0.2, adding water, stirring until no bubbles are generated, washing, filtering, drying to obtain black solid powder, and finally, treating the black solid powder in a muffle furnace at 650 ℃ for 3 hours to obtain the waste lithium cobaltate cathode material.
(2) Dissolving 0.2251g of manganese acetate tetrahydrate in 2.67mL of ultrapure water, adding 0.2g of waste lithium cobaltate anode material, wherein the solid-to-liquid ratio of the lithium cobaltate anode material to the manganese acetate solution is 75g/L, placing the mixture in a reaction kettle for hydrothermal reaction at 160 ℃ for 12 hours, and filtering to obtain a leaching solution and leaching residues.
(3) The leaching rate of lithium in the lithium cobalt oxide cathode material is 93.68 percent and the leaching rate of cobalt is 0.13 percent by ICP-OES, and the leaching selectivity of lithium reaches 99.86 percent.
The lithium cobaltate and the lithium nickel cobalt manganese oxide are both positive electrode materials with layered structures, and the lithium selective leaching effect of divalent manganese ions on the lithium cobaltate positive electrode materials is better under the same conditions, and the possible reason is that the lithium cobaltate structure is simpler than that of the lithium nickel cobalt manganese oxide, and no matter the lithium cobaltate is a waste lithium cobalt oxide or lithium nickel cobalt manganese oxide ternary positive electrode material, the divalent manganese ions can be subjected to hydrolysis reaction by virtue of a lower oxidation-reduction potential of the divalent manganese ions in the hydrothermal reaction to provide electrons for inducing the transition metal valence state of the positive electrode materials to change, so that the lithium in the positive electrode materials can be efficiently selectively leached.
Example 7
This example was identical to example 1 except that the ex-service batteries were pre-treated by manual disassembly of example 1 and sorted by commercial equipment. The method specifically comprises the following steps:
(1) Discharging the retired battery in a saturated NaCl solution for 12 hours, putting the retired battery into a lithium battery crushing and sorting integrated device, enabling the battery to obtain a mixture containing a positive electrode material, negative electrode graphite, iron sheets, an aluminum foil and a copper foil through a coarse crushing and sorting device, sequentially separating the iron sheets through a magnetic separation device, separating nonmetal materials such as the negative electrode graphite through a winnowing device, separating copper and aluminum through a heating device to obtain black solid powder, and finally placing the black solid powder in a muffle furnace to be treated at 650 ℃ for 3 hours to obtain the waste ternary positive electrode material.
(2) Dissolving 0.2521g of tetrahydrate manganese acetate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery anode material, placing the lithium ion battery anode material and manganese acetate solution in a reaction kettle at 200 ℃ for hydrothermal reaction for 24 hours, and filtering to obtain leachate and leaching residues.
(3) The leaching rate of lithium in the positive electrode material is 91.86 percent, the leaching rate of nickel is 0.74 percent, the leaching rate of cobalt is 0.10 percent and the leaching selectivity of lithium reaches 99.09 percent by ICP-OES. Manganese ions can not be detected in the leaching solution, so the lithium-rich leaching solution can be recycled to prepare lithium carbonate.
(4) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture of lithium, nickel, cobalt and manganese elements with a molar ratio of 1.30:0.43:0.42:1, 0.1492g of lithium acetate, 0.1790g of nickel acetate tetrahydrate and 0.1761g of cobalt acetate tetrahydrate are added to meet the conditions of 1.05:0.33:0.33:0.33 molar ratio.
(5) And uniformly mixing the mixture, pre-calcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining the pre-calcined product for 10 hours at 850 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
(6) A lithium sheet is used as a negative electrode, a regenerated positive electrode material is assembled into a button half-cell, the cyclic charge and discharge performance of the button half-cell under the multiplying power of 0.5C (1C = 230mAh/g) is measured by using a cell test system, the initial discharge specific capacity is 116.5mAh/g, and the capacity retention rate is 84.1% after 100 times of charge and discharge.
Therefore, no matter manual disassembly or industrial equipment disassembly and sorting are carried out for pretreatment, only the retired lithium ion battery is sequentially subjected to discharging, disassembly, crushing, sorting, aluminum foil removal and binder removal through calcination, so that the anode material obtained through pretreatment is subjected to lithium recovery and anode material regeneration through the method, and the lithium leaching rate and the electrochemical performance of the regenerated anode material are basically the same.
In order to facilitate comparison of the necessity of the method of the present invention, the advantages of the present invention will be described with reference to comparative examples.
Comparative example 1
The procedure for the pretreatment of the ex-service batteries was the same as in example 1.
(1) Adding 0.2g of the retired lithium ion battery anode material into 2.67mL of ultrapure water, placing the cathode material and the aqueous solution in a reaction kettle for hydrothermal reaction at 160 ℃ for 12h, and filtering to obtain a leaching solution, wherein the solid-to-liquid ratio of the anode material to the aqueous solution is 75 g/L.
(2) The leaching rate of the anode material lithium measured by ICP-OES is 5.71%, the leaching rate of nickel is 0%, the leaching rate of cobalt is 0%, and the leaching selectivity of lithium reaches 100%.
The comparative example shows that the leaching rate of lithium is extremely low after the waste cathode material is treated by using ultrapure water in the hydrothermal reaction system, and the divalent manganese ions are the main active substances for high-efficiency selective leaching of lithium.
Comparative example 2
The procedure for the pretreatment of the ex-service batteries was the same as in example 1.
(1) Dissolving 0.0844g of anhydrous sodium acetate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery cathode material, placing the cathode material and the sodium acetate solution in a reaction kettle at 160 ℃ for hydrothermal reaction for 12 hours, and filtering to obtain a leaching solution, wherein the solid-to-liquid ratio of the cathode material to the sodium acetate solution is 75 g/L.
(2) The leaching rate of lithium in the positive electrode material is 18.13 percent, the leaching rate of nickel is 0 percent, the leaching rate of cobalt is 0 percent, and the leaching selectivity of lithium reaches 100 percent by ICP-OES.
The comparative example shows that the leaching rate of lithium is very low after the waste cathode material is treated by using the sodium acetate solution in the hydrothermal reaction system, which indicates that the divalent manganese ions are the main active substance for efficient and selective leaching of lithium.
Fig. 6 is a graph comparing the leaching rates of lithium nickel cobalt under different conditions of examples 1 to 5 and comparative examples 1 to 2, and it can be seen that the overall leaching rate is higher when divalent manganese ions are used for hydrothermal reaction with the waste ternary cathode material in examples 1 to 5 to leach lithium ions therein, and particularly, the leaching effect is better when manganese acetate is used in example 1 compared with other manganese salts. The comparative examples 1 and 2 respectively adopt pure water and sodium acetate for hydrothermal leaching, have poor leaching effect on lithium ions in the waste anode material, and show that the divalent manganese ions are main active substances in the hydrothermal selective leaching lithium reaction.
Comparative example 3
The procedure for pretreating the ex-service batteries was the same as in example 1.
(1) Waste anode materials in the retired lithium ion battery are directly used as raw materials of regenerated anode materials without hydrothermal treatment. Taking 0.2g of waste anode material, and determining the molar ratio of lithium, nickel, cobalt and manganese elements in the waste anode material to be 2.82 through ICP-OES: 1:0.98:0.96, supplemented with 0.0147g of lithium acetate, 0.0032g of cobalt acetate tetrahydrate, 0.0061g of manganese acetate tetrahydrate to make it meet the conditions of 1.05:0.33:0.33:0.33 mole ratio.
(2) And uniformly mixing the mixture, pre-calcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a pre-calcined product, uniformly grinding the pre-calcined product, and continuously calcining the pre-calcined product for 10 hours at 850 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
(3) A lithium sheet is used as a negative electrode, a button half-cell is assembled by a regenerated positive electrode material, the cyclic charge and discharge performance of the button half-cell under the multiplying power of 0.5C (1C = 230mAh/g) is measured by a cell testing system, the initial discharge specific capacity is 81.5mAh/g, and the capacity retention rate is only 49.6% after 100 times of charge and discharge.
The comparative example shows that the waste positive electrode material is directly regenerated into the nickel cobalt lithium manganate positive electrode material without being subjected to lithium leaching treatment, and the regenerated positive electrode material is very poor in electrochemical performance and cycling stability. The electrochemical performance and the cycling stability of the regenerated cathode material can be obviously improved by using the residue after lithium is selectively leached by the divalent manganese ions as a raw material, which is probably because the structure of the cathode is damaged at the same time of the lithium leaching process, so that the cathode becomes loose and porous (by observing an SEM image shown in figure 7, the structure of the cathode material of the comparative example 3 is not as loose as that of the cathode material of the example 1), and the sufficient reaction and structural rearrangement in the regeneration process are facilitated, so that the regenerated cathode material with good performance is formed.
Comparative example 4
The procedure for pretreating the ex-service batteries was the same as in example 1.
(1) Dissolving 0.2560g of nickel acetate tetrahydrate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery cathode material, placing the cathode material and the nickel acetate solution in a reaction kettle at the solid-to-liquid ratio of 75g/L for hydrothermal reaction at 200 ℃ for 24h, and filtering to obtain a leaching solution and leaching residues.
(2) The lithium leaching rate of the positive electrode material was measured to be 52.76%, the cobalt leaching rate was measured to be 0.61%, the manganese leaching rate was measured to be 0.45%, and the lithium leaching selectivity was measured to be 98.03%. The leachate also contains more than 70% of unreacted nickel ions, so the lithium and nickel ions need to be separated before the leachate is recovered into lithium carbonate.
(3) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture of lithium, nickel, cobalt and manganese with the molar ratio of 1.71:1:0.53:0.53, 0.1433g of lithium acetate, 0.1092g of cobalt acetate tetrahydrate and 0.1079g of manganese acetate tetrahydrate are added to make it conform to the 1.05:0.33:0.33:0.33 molar ratio.
(4) And uniformly mixing the mixture, firstly precalcining for 5 hours at 500 ℃ in the air atmosphere to obtain a precalcined product, then uniformly grinding the precalcined product, and continuously calcining for 10 hours at 850 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate positive electrode material.
(5) A lithium sheet is used as a negative electrode, a button half-cell is assembled by a regenerated positive electrode material, the cyclic charge and discharge performance of the button half-cell under the multiplying power of 0.5C (1C = 230mAh/g) is measured by a cell testing system, the initial discharge specific capacity is 96.1mAh/g, and the capacity retention rate is 87.4% after 100 times of charge and discharge.
The comparison example shows that after the waste positive electrode material is subjected to the hydrothermal treatment by the divalent nickel ion solution, the leaching rate of lithium is low, a large amount of divalent nickel ions remain in the solution, and lithium and nickel elements need to be further separated to be recovered and prepare lithium carbonate. This is probably because the oxidation-reduction potential of divalent nickel ions in the aqueous solution is higher and hydrolysis reaction is more difficult to occur, so that oxidation reaction is more difficult to occur than divalent manganese ions in the hydrothermal process, and it is difficult to induce the valence state change of transition metal in the positive electrode material, thereby releasing a large amount of lithium ions. Due to the low lithium leaching rate, the structural damage of the cathode material is not complete (by observing the SEM image shown in FIG. 7, the structural damage degree of the cathode material in comparative example 4 is not as high as that of the cathode material in example 1), so that the electrochemical performance of the nickel cobalt lithium manganate cathode material regenerated by the residue is poor.
Comparative example 5
The procedure for the pretreatment of the ex-service batteries was the same as in example 1.
(1) Dissolving 0.2562g of cobalt acetate tetrahydrate in 2.67mL of ultrapure water, adding 0.2g of retired lithium ion battery cathode material, placing the cathode material and the cobalt acetate solution in a reaction kettle at the solid-to-liquid ratio of 75g/L for hydrothermal reaction at 200 ℃ for 24 hours, and filtering to obtain a leaching solution and leaching residues.
(2) The leaching rate of lithium was 67.36%, the leaching rate of nickel was 0.24%, the leaching rate of manganese was 0.14%, and the leaching selectivity of lithium was 99.43% as measured by ICP-OES. More than 38% of unreacted divalent cobalt ions remain in the leachate, so that lithium and cobalt elements in the leachate need to be further separated to be recovered and prepared into lithium carbonate.
(3) Uniformly mixing the recovered lithium carbonate with 0.2g of leaching residue, and detecting by ICP-OES to obtain a mixture with a molar ratio of lithium, nickel, cobalt and manganese elements of 1.40:0.46:1:0.44, 0.2053g of lithium acetate, 0.1518g of nickel acetate tetrahydrate and 0.1532g of manganese acetate tetrahydrate are added to make it conform to the 1.05:0.33:0.33:0.33 mole ratio.
(4) And uniformly mixing the mixture, firstly precalcining the mixture for 5 hours at 500 ℃ in the air atmosphere to obtain a precalcined product, then uniformly grinding the precalcined product, and continuously calcining the product for 10 hours at 850 ℃ in the air atmosphere to obtain the regenerated nickel cobalt lithium manganate cathode material.
(5) A lithium sheet is used as a negative electrode, a regenerated positive electrode material is assembled into a button half-cell, the cyclic charge and discharge performance of the button half-cell under the multiplying power of 0.5C (1C = 230mAh/g) is measured by using a cell test system, the initial discharge specific capacity is 106.3mAh/g, and the capacity retention rate is 83.6% after 100 times of charge and discharge.
The comparative example shows that the leaching rate of lithium is lower after the waste positive electrode material is subjected to the hydrothermal treatment by the divalent cobalt ion solution. This is probably because the higher redox potential of the divalent cobalt ions in the aqueous solution is, the weaker self-hydrolysis reaction capability is, the slower oxidation reaction occurs than that of the divalent manganese ions in the hydrothermal process, and it is difficult to induce the change of the valence state of the transition metal in the positive electrode material, thereby releasing a large amount of lithium ions. Since lithium is not leached in a large amount, the structure of the positive electrode material is slightly loose due to partial lithium leaching (by observing an SEM image shown in figure 7, compared with comparative example 3 and comparative example 4, the structure of the positive electrode material in comparative example 5 is slightly loose, but the structure of the positive electrode material is not as loose as that of the positive electrode material in example 1), so that the electrochemical performance of the nickel cobalt lithium manganate positive electrode material regenerated by residues is poorer than that of the divalent manganese ion leaching residues short-process regenerated positive electrode material, but is better than that of the divalent nickel ion leaching residues short-process regenerated positive electrode material.
As can be seen from comparative examples 4 to 5, the leaching rate of lithium is low when the divalent nickel ions or divalent cobalt ions are used for hydrothermally treating the waste positive electrode material of the retired lithium ion battery, and the reason is mainly that the divalent nickel ions and the divalent cobalt ions are difficult to generate oxidation reaction to generate electrons to induce the positive electrode material to release lithium. The reason for this is probably that divalent nickel ions and divalent cobalt ions both have higher oxidation-reduction potentials, are weak in self-hydrolysis oxidation capacity and cannot function in the hydrothermal reaction, and divalent manganese ions have lower oxidation-reduction potentials and thus have stronger hydrolysis capacity, so that oxidation reaction is easy to occur during hydrothermal treatment, electrons are provided for the positive electrode material, so that transition metals in the positive electrode material are induced to change in valence state, and a large amount of lithium is released.
FIG. 8 is a graph comparing the specific discharge capacity of the regenerated lithium nickel cobalt manganese oxide positive electrode material of example 1 and comparative examples 3-5 under different conditions, which is cycled for 100 times under the rate of 0.5C. As can be seen from the figure, the electrochemical performance of the cathode material regenerated in example 1 is obviously better than that of the regenerated cathode materials in comparative examples 3, 4 and 5, the cyclic charge and discharge performance at the rate of 0.5C (1c = 230mah/g) is 117.2mAh/g, and the capacity retention rate after 100 times of charge and discharge is 82.0%. The positive electrode material directly regenerated without hydrothermal leaching of comparative example 3 was the worst performance.
Comparative example 6
The procedure for the pretreatment of the ex-service batteries was the same as in example 1.
(1) Weighing 0.2g of the retired lithium ion battery anode material, adding the retired lithium ion battery anode material into a zirconia ball milling tank, and then adding 0.2521g of tetrahydrate manganese acetate solid according to a ball-to-material ratio of 10:1 adding 4.5g of zirconia balls with the diameter of 4mm, and putting the zirconia balls into a high-energy ball mill to perform ball milling for 6 hours under the condition of 500 rpm.
(2) And (3) after the ball milling is finished, washing the ball milling tank by ultrapure water, filtering to obtain a leaching solution and leaching residues, diluting the leaching solution to a proper multiple, and measuring the leaching rate of lithium by using ICP-OES to be 4.20%, the leaching rate of nickel to be 0.06% and cobalt not detected (namely the leaching rate of cobalt to be 0%). The leachate still contains a large amount of manganese residues, and the calculated manganese residue rate is 101.37%, which means that manganese acetate does not participate in the reaction.
Fig. 9 is a graph comparing the leaching rate of lithium nickel cobalt and the manganese residual rate of example 1 and comparative example 6. In contrast to hydrothermal treatment, the use of manganese acetate in ball milling for the treatment of waste cathode materials does not allow efficient lithium leaching. The reason for this is probably that the mechanochemical action of ball milling cannot cause the hydrolysis capacity of the divalent manganese ions to play a role, and the divalent manganese ions cannot undergo oxidation reaction in the ball milling method and cannot induce the positive electrode material to release lithium. It can be concluded that the self-hydrolysis ability of the divalent manganese ions is likely to function only in the hydrothermal reaction at high temperature and high pressure, and further the lithium in the cathode material is selectively leached efficiently.
It will be understood by those skilled in the art that the foregoing is only an exemplary embodiment of the present invention, and is not intended to limit the invention to the particular forms disclosed, since various modifications, substitutions and improvements within the spirit and scope of the invention are possible and within the scope of the appended claims.

Claims (10)

1. A method for recovering lithium from a retired lithium battery is characterized by comprising the following steps:
(1) Sequentially pretreating retired lithium batteries to obtain waste positive electrode materials;
(2) Mixing the waste positive electrode material obtained in the step (1) with a water solution of divalent manganese ions, and carrying out hydrothermal reaction under a closed condition, wherein the divalent manganese ions are subjected to oxidation reaction to generate MnO 2 Transferring electrons to the waste anode material to induce the transition metal in the waste anode material to perform a reduction reaction and release lithium ions into the solution, performing solid-liquid separation after the reaction is finished to obtain a leaching solution and leaching residues, wherein the leaching solution is a lithium-rich solution, and the leaching residues contain MnO generated by the reaction 2 And transition metals in the waste cathode material;
(3) And (3) carrying out precipitation reaction on the lithium-rich solution obtained in the step (2) by adopting carbonate to obtain a lithium carbonate product.
2. The method of claim 1, wherein the main component of the waste cathode material in the step (1) is at least one of lithium nickel cobalt manganese oxide, lithium cobalt oxide and lithium nickel oxide.
3. The method according to claim 1, wherein the aqueous solution of divalent manganese ions in step (2) is at least one of a manganese acetate solution, a manganese oxalate solution, a manganese chloride solution, a manganese sulfate solution and a manganese nitrate solution, preferably a manganese acetate solution.
4. The method of claim 1, wherein the molar ratio of the divalent manganese ions to the lithium ions in the waste cathode material in step (2) is (0.25-1): 1; the solid-to-liquid ratio of the waste anode material to the aqueous solution of the divalent manganese ions is 25-200 g/L.
5. The method of claim 1, wherein the hydrothermal reaction in step (2) is carried out at a reaction temperature of 100 to 220 ℃ for a reaction time of 1 to 28 hours.
6. The method of claim 1, wherein the carbonate in step (3) is at least one of sodium carbonate, ammonium carbonate and potassium carbonate.
7. A method for regenerating a nickel-cobalt-manganese positive electrode material using the leaching residue and the lithium carbonate product obtained in the method for recovering lithium according to any one of claims 1 to 6, comprising the steps of:
s1: uniformly mixing the leaching residue and lithium carbonate, and measuring the content of each metal element;
s2: according to the proportion requirement of each element in the regenerated anode material, adding a proper amount of lithium salt, nickel salt, cobalt salt and manganese salt, and uniformly mixing;
s3: and (3) calcining the mixture uniformly mixed in the step (S2) in an air atmosphere to obtain the regenerated lithium nickel cobalt manganese oxide positive electrode material.
8. The method according to claim 7, wherein the ratio of lithium, nickel, cobalt and manganese elements in the regenerated positive electrode material in the step S2 is 1.05:0.3:0.3:0.3, 1.05:0.8:0.1:0.1 or 1.05:0.5:0.2:0.3;
the lithium salt in the step S2 is at least one or a combination of lithium carbonate, lithium hydroxide, lithium acetate and lithium nitrate; the nickel salt is at least one or a plurality of combinations of nickel acetate, nickel sulfate and nickel nitrate, and the cobalt salt is at least one or a plurality of combinations of cobalt acetate, cobalt sulfate and cobalt nitrate; the manganese salt is at least one or a combination of manganese acetate, manganese sulfate and manganese nitrate.
9. The method of claim 7, wherein step S3 comprises the sub-steps of:
s301: pre-calcining the mixture uniformly mixed in the step S2 in an air atmosphere to preliminarily form the mixture;
s302: grinding the preliminarily formed product, and then carrying out secondary calcination in the air atmosphere to obtain the regenerated lithium nickel cobalt manganese oxide cathode material.
10. The process according to claim 9, wherein the precalcination has a calcination temperature of between 400 and 600 ℃ and a precalcination time of between 3 and 7 hours; the second calcination has the calcination temperature of 750-950 ℃ and the calcination time of 8-12 h.
CN202210937394.8A 2022-08-05 2022-08-05 Method for recovering lithium from retired lithium battery and regenerating positive electrode material Pending CN115275415A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115724474A (en) * 2022-11-16 2023-03-03 清华大学深圳国际研究生院 Repairing method of failed layered positive electrode material, positive electrode material and application of positive electrode material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115724474A (en) * 2022-11-16 2023-03-03 清华大学深圳国际研究生院 Repairing method of failed layered positive electrode material, positive electrode material and application of positive electrode material
CN115724474B (en) * 2022-11-16 2023-12-08 清华大学深圳国际研究生院 Repairing method of failed layered positive electrode material, positive electrode material and application of positive electrode material

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