CN116553605A - Recycling method of waste lithium titanate electrode slice, lithium titanate material and application - Google Patents
Recycling method of waste lithium titanate electrode slice, lithium titanate material and application Download PDFInfo
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- CN116553605A CN116553605A CN202310664771.XA CN202310664771A CN116553605A CN 116553605 A CN116553605 A CN 116553605A CN 202310664771 A CN202310664771 A CN 202310664771A CN 116553605 A CN116553605 A CN 116553605A
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 216
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 216
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 213
- 239000000463 material Substances 0.000 title claims abstract description 116
- 238000000034 method Methods 0.000 title claims abstract description 72
- 238000004064 recycling Methods 0.000 title claims abstract description 66
- 239000002699 waste material Substances 0.000 title claims abstract description 31
- 239000000203 mixture Substances 0.000 claims abstract description 83
- 239000007787 solid Substances 0.000 claims abstract description 60
- 238000001354 calcination Methods 0.000 claims abstract description 32
- 239000007788 liquid Substances 0.000 claims abstract description 27
- 238000000926 separation method Methods 0.000 claims abstract description 27
- 238000011084 recovery Methods 0.000 claims abstract description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 7
- 239000001301 oxygen Substances 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 23
- 239000011248 coating agent Substances 0.000 claims description 12
- 238000000576 coating method Methods 0.000 claims description 12
- 238000001035 drying Methods 0.000 claims description 12
- 230000005611 electricity Effects 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 12
- 238000001914 filtration Methods 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 8
- 238000000967 suction filtration Methods 0.000 claims description 7
- 238000002360 preparation method Methods 0.000 claims description 4
- 238000005119 centrifugation Methods 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 3
- 238000005374 membrane filtration Methods 0.000 claims description 3
- 238000001471 micro-filtration Methods 0.000 claims description 3
- 238000001728 nano-filtration Methods 0.000 claims description 3
- 239000012465 retentate Substances 0.000 claims description 3
- 238000001223 reverse osmosis Methods 0.000 claims description 3
- 238000000108 ultra-filtration Methods 0.000 claims description 3
- 238000004062 sedimentation Methods 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 10
- 230000007613 environmental effect Effects 0.000 abstract description 5
- 239000000243 solution Substances 0.000 description 22
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 239000012065 filter cake Substances 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 239000003960 organic solvent Substances 0.000 description 5
- 239000008367 deionised water Substances 0.000 description 4
- 229910021641 deionized water Inorganic materials 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 239000002033 PVDF binder Substances 0.000 description 3
- 239000003929 acidic solution Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000001000 micrograph Methods 0.000 description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910003002 lithium salt Inorganic materials 0.000 description 2
- 159000000002 lithium salts Chemical class 0.000 description 2
- 150000003608 titanium Chemical class 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000011267 electrode slurry Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- -1 titanium dioxide Chemical class 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/003—Titanates
- C01G23/005—Alkali titanates
-
- 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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
-
- 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
- H01M2004/027—Negative 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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- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The application discloses a recycling method of a waste lithium titanate electrode slice, a lithium titanate material and application, wherein the recycling method comprises the following steps: separating lithium titanate in the lithium titanate electrode plate from an electrode current collector in a solution environment by taking the lithium titanate electrode plate as a recovery object to obtain a first mixture containing the lithium titanate and the electrode current collector; removing and recovering the electrode current collector in the first mixture to obtain a second mixture containing lithium titanate; performing solid-liquid separation on the second mixture to obtain a solid third mixture; and calcining the third mixture in an atmosphere containing oxygen to obtain the lithium titanate material, wherein the method has the advantages of simple flow, low equipment requirement, easy control of process conditions, low cost, safety and environmental protection, and the recovered lithium titanate material can be used for preparing lithium titanate batteries.
Description
Technical Field
The application relates to the technical field of electrolyzed water, in particular to a recycling method of a waste lithium titanate electrode slice, a lithium titanate material and application.
Background
With the rapid development of electronic technology, the requirements of various electronic products on power supplies are continuously improved. The lithium battery has the advantages of high energy density, long cycle life, no memory effect and the like, and is widely applied. The lithium titanate battery belongs to one of important members of the lithium battery, has the advantages of ultra-high safety (nonflammable and non-explosive), ultra-long service life (about 30000 times), wide working range of high and low temperature (-40-65 ℃), high power and low cost, is one of research hotspots of the current lithium battery, and has wide application prospect.
In the lithium titanate battery, the lithium titanate material is used as one of the negative electrode materials, and has the advantages of high specific capacity, strong structural stability, good cycle stability and the like. The lithium titanate is expensive, so that the application and development of the lithium titanate battery are limited, and a great number of waste lithium titanate pole pieces can be generated in the preparation and use processes of the lithium titanate battery, and no effective recycling method is available for the waste lithium titanate pole pieces at present, so that lithium titanate in the waste lithium titanate pole pieces cannot be effectively recycled, and resource waste is caused.
Therefore, how to provide a recycling method for the waste lithium titanate pole piece has important significance for the application and development of the lithium titanate battery.
Disclosure of Invention
The application provides a recycling method of a waste lithium titanate electrode slice, a lithium titanate material and application thereof, so as to respectively recycle lithium titanate and an electrode current collector in the waste lithium titanate electrode slice, thereby avoiding resource waste.
The technical scheme of the application is as follows:
in a first aspect, the present application provides a recycling method of a waste lithium titanate electrode slice, including the following steps:
providing a lithium titanate electrode sheet, wherein the lithium titanate electrode sheet comprises an electrode current collector and a first coating coated on the electrode current collector, the material of the first coating comprises lithium titanate, and the lithium titanate is separated from the electrode current collector in a solution environment to obtain a first mixture comprising the lithium titanate and the electrode current collector;
removing and recovering the electrode current collector in the first mixture to obtain a second mixture comprising the lithium titanate;
performing solid-liquid separation on the second mixture to obtain a solid third mixture, wherein the third mixture comprises the lithium titanate; and
and calcining the third mixture in an atmosphere containing oxygen to obtain the lithium titanate material.
Optionally, the step of separating the lithium titanate from the electrode current collector in the environment of a solution includes: placing the lithium titanate electrode sheet in the solution, and separating the lithium titanate from the electrode current collector under stirring; and/or
The solution is water.
Optionally, the removing and recovering the electrode current collector in the first mixture includes the steps of: and filtering the first mixture to obtain a retentate which is the electrode current collector.
Optionally, the filtering the first mixture includes the steps of: filtering the first mixture with a 100 mesh to 300 mesh screen; wherein the lithium titanate in the first mixture passes through the mesh, the mesh trapping the electrode current collector.
Optionally, in the step of subjecting the second mixture to solid-liquid separation, the solid-liquid separation includes one or more of suction filtration, centrifugation, reverse osmosis, membrane filtration, nanofiltration, ultrafiltration, microfiltration, and gravity settling.
Optionally, after the step of performing solid-liquid separation on the second mixture and before the step of obtaining a third mixture in a solid state, the recycling method further includes the steps of: collecting a first solid obtained through solid-liquid separation, performing one or more times of water washing treatment on the first solid, and then drying to obtain a second solid; the third mixture is the second solid;
alternatively, after the step of performing solid-liquid separation on the second mixture and before the step of obtaining a third mixture in a solid state, the recycling method further includes the steps of: collecting a first solid obtained through solid-liquid separation, and crushing the first solid to obtain a third solid with 50-300 meshes; the third mixture is the third solid;
alternatively, after the step of performing solid-liquid separation on the second mixture and before the step of obtaining a third mixture in a solid state, the recycling method further includes the steps of: collecting a first solid obtained through solid-liquid separation, performing one or more times of water washing treatment on the first solid, and then drying to obtain a second solid; crushing the second solid to obtain a fourth solid with 50-300 meshes; the third mixture is the fourth solid.
Optionally, the calcination treatment is performed at a pressure of 0.2Mpa to 0.6 Mpa; and/or
The temperature of the calcination treatment is 550-760 ℃; and/or
The mass of the third mixture is 100 g-300 g, and the calcination treatment time is 1 h-4 h.
In a second aspect, the present application further provides a lithium titanate material, where the lithium titanate material is recovered by any one of the recycling methods described above.
Optionally, the first charge capacity of the lithium titanate material under the condition of 1C of electricity buckling is 130 mAh/g-160 mAh/g, and/or the first discharge capacity of the lithium titanate material under the condition of 1C of electricity buckling is 130 mAh/g-160 mAh/g, and/or the first charge-discharge efficiency of the lithium titanate material under the condition of 1C of electricity buckling is greater than 98%.
In a third aspect, the present application further provides a recycling method according to any one of the first aspects, or an application of the lithium titanate material according to any one of the second aspects in the preparation of a lithium titanate battery.
The application provides a recycling method of a waste lithium titanate electrode slice, a lithium titanate material and application, and the recycling method has the following technical effects:
in the recycling method, the lithium titanate electrode plate is taken as a recycling object, the lithium titanate in the lithium titanate electrode plate is separated from the electrode current collector, and then the electrode current collector and the lithium titanate are recycled respectively, so that the original structure of the lithium titanate is effectively maintained in the whole recycling process, and the recycling method has the advantages of simple flow, low equipment requirement, easy control of process conditions, low cost and safety and environmental protection, the first charge capacity of the recycled lithium titanate material under the 1C condition of power-on can reach 158.2mAh/g, the first discharge capacity can reach 158.6mAh/g, and the first charge-discharge efficiency can reach 100.26%, so that the recycled lithium titanate material can be used for preparing lithium titanate batteries.
Drawings
Technical solutions and other advantageous effects of the present application will be made apparent from the following detailed description of specific embodiments of the present application with reference to the accompanying drawings.
Fig. 1 is a schematic flow chart of a method for recycling a waste lithium titanate electrode sheet according to an embodiment of the present application;
FIG. 2 is an X-ray diffraction analysis chart of the lithium titanate material recovered in example 1;
FIG. 3 is a scanning electron microscope image of the lithium titanate material recovered in example 1;
FIG. 4 is a scanning electron microscope image of the calcined material of example 2;
FIG. 5 is a scanning electron microscope image of the calcined material of example 3.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art and materials or reagents used in the examples and comparative examples of this application are commercially available. In addition, any methods and materials similar or equivalent to those described herein can be used in the present invention. The preferred methods and materials described herein are illustrative only and should not be construed as limiting the scope of the present application.
The following description of the embodiments is not intended to limit the preferred embodiments. Various embodiments of the present application may exist in a range of forms; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; it is therefore to be understood that the range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the ranges, such as 1, 2, 3, 4, 5, and 6, wherever applicable. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.
In the description of the present application, the term "comprising" means "including but not limited to".
The term "plurality of", "multiple", or the like means two (times) or more, and for example, may be two (times), three (times), four (times), five (times), six (times), or the like.
The scope of the term "and/or" includes any one of the two or more items listed in relation to each other as well as any and all combinations of items listed in relation to each other, including any two items listed in relation to each other, any more items listed in relation to each other, or all combinations of items listed in relation to each other. For example, "a and/or B" includes A, B and a+b three parallel schemes. For another example, the technical schemes of "a, and/or B, and/or C, and/or D" include any one of A, B, C, D (i.e., the technical scheme of "logical or" connection), and also include any and all combinations of A, B, C, D, i.e., any two or three of A, B, C, D, and also include four combinations of A, B, C, D (i.e., the technical scheme of "logical and" connection).
The embodiment of the application provides a recycling method of a waste lithium titanate electrode slice, as shown in fig. 1, comprising the following steps:
s1, providing a lithium titanate electrode plate, wherein the lithium titanate electrode plate comprises an electrode current collector and a first coating coated on the electrode current collector, the material of the first coating comprises lithium titanate, and the lithium titanate is separated from the electrode current collector in a solution environment to obtain a first mixture comprising the lithium titanate and the electrode current collector;
s2, removing and recycling the electrode current collector in the first mixture to obtain a second mixture containing lithium titanate;
s3, carrying out solid-liquid separation on the second mixture to obtain a solid third mixture, wherein the third mixture comprises lithium titanate;
and S4, calcining the third mixture in an atmosphere containing oxygen to obtain the lithium titanate material.
In the recycling method of the embodiment of the application, the lithium titanate electrode plate is taken as a recycling object, the lithium titanate in the lithium titanate electrode plate is separated from the electrode current collector, and then the electrode current collector and the lithium titanate are recycled respectively, so that the original structure of the lithium titanate is effectively maintained in the whole recycling process, and the recycling method has the advantages of simple flow, low equipment requirement, easiness in controlling process conditions, lower cost, safety and environmental friendliness.
Specifically, in step S1, the lithium titanate electrode sheet may be obtained by subjecting a discarded battery or cell to a self-discharge, disassembly, or other steps, and the electrode current collector is made of, for example, aluminum foil. It is understood that the solution does not chemically react with lithium titanate in the lithium titanate electrode sheet to avoid damaging the structure of the lithium titanate; the solution and the electrode current collector in the lithium titanate electrode sheet can not react chemically, so that the structure of the electrode current collector is prevented from being damaged. The solution may be a neutral solution (e.g., pH 7-7.5) and the solution may be, for example, water.
In order to avoid damage to the structures of the lithium titanate and the electrode current collector in the lithium titanate electrode sheet and to ensure the safety and environmental protection of recovery, in some embodiments of the present application, the step of separating the lithium titanate from the electrode current collector in the environment of the solution includes: a lithium titanate electrode sheet was placed in the solution, and lithium titanate was separated from the electrode current collector with stirring.
It should be noted that, if the solution is an acidic solution (e.g., pH less than 7) or an alkaline solution (e.g., pH greater than 7.5), the acidic solution or the alkaline solution may chemically react with the electrode current collector, thereby destroying the original structure of the electrode current collector, so that the metal element in the electrode current collector enters the solution in an ionic form, thereby improving the difficulty of recovering the electrode current collector and increasing the recovery cost; in the second aspect, the acidic solution can chemically react with lithium titanate, so that the original structure of the lithium titanate is damaged, only lithium salts (such as lithium carbonate) and titanium salts (such as titanium dioxide, metatitanic acid and the like) can be recovered and obtained, and the recovered lithium salts and titanium salts are recycled to chemically synthesize the lithium titanate, so that the recovery process is complicated and complicated, and the recovery cost is increased; in the third aspect, the recovery apparatus is required to have acid resistance or alkali resistance, and the demand for the apparatus is higher.
If the solution is an organic solvent, there are problems: in the first aspect, in the subsequent recovery process, the organic solvent is not easy to remove, so that the recovery difficulty is increased; in the second aspect, the organic solvent is expensive, resulting in an increase in recovery cost; in the third aspect, the organic solvent has peculiar smell, and part of the organic solvent has inflammability and explosiveness, which is not beneficial to safety and environmental protection.
For ease of operation, in some embodiments of the present application, the step of separating lithium titanate from the electrode current collector in the environment of the solution is performed in a reaction vessel equipped with a stirring paddle. In order to facilitate separation of the lithium titanate from the electrode current collector, the lithium titanate electrode sheet may be cut into pieces and then placed in a reaction vessel containing the solution (e.g., water). The stirring speed may be 400r/min to 600r/min, for example, 400r/min, 500r/min, 600r/min, or a value between any two of the above values.
For ease of operation and control, in some embodiments of the present application, step S2 includes: the first mixture is subjected to filtration treatment, and the obtained retentate is an electrode current collector. And cleaning, drying and other procedures are carried out on the trapped electrode current collector, so that recovery is realized. It is understood that the apparatus for implementing the filtering process is not particularly limited as long as it is capable of separating lithium titanate from an electrode current collector.
As an example, the step of subjecting the first mixture to a filtration process comprises: filtering the first mixture with a screen; wherein lithium titanate in the first mixture passes through the mesh and the mesh entraps the electrode current collector. The mesh number of the screen may be 100 mesh to 300 mesh, for example, 100 mesh, 200 mesh, 300 mesh, and values between any two of the foregoing.
In step S3, the purpose of the solid-liquid separation of the second mixture is to: the solvent is removed to facilitate recovery of the lithium titanate. The solid-liquid separation includes, but is not limited to, one or more of suction filtration, centrifugation, reverse osmosis, membrane filtration, nanofiltration, ultrafiltration, microfiltration, and gravity settling. As an example, the solid-liquid separation is suction filtration.
In order to increase the purity of the recovered lithium titanate material, in some embodiments of the present application, for step S3, after the step of solid-liquid separating the second mixture and before the step of obtaining a third mixture in a solid state, the recycling method further comprises the steps of: collecting a first solid obtained through solid-liquid separation, performing one or more times of water washing treatment on the first solid, and then drying to obtain a second solid; the second solid is the third mixture. Wherein the purpose of the water washing treatment is to remove soluble impurity ions including but not limited toThus Na is + 、Mg 2+ 、SO 4 2- PO (Positive and negative) 4 3- . The drying includes, but is not limited to, a process such as heating and vacuum drying, and the drying may be, for example: and (5) placing the material obtained after the water washing treatment in a blast drying oven for heating and drying.
As an alternative embodiment, in order to increase the purity of the recovered lithium titanate material, in other examples of the present application, for step S3, the recycling method further comprises the steps of: collecting a first solid obtained through solid-liquid separation, and crushing the first solid to obtain a third solid with 50-300 meshes; the third solid is the third mixture.
As an alternative embodiment, in order to increase the purity of the recovered lithium titanate material, in other examples of the present application, for step S3, the recycling method further comprises the steps of: collecting a first solid obtained through solid-liquid separation, performing one or more times of water washing treatment on the first solid, and then drying to obtain a second solid; crushing the second solid to obtain a fourth solid with 50-300 meshes; the fourth solid is the third mixture.
Materials based on the coating of lithium titanate electrode sheets typically also contain conductive carbon black and a binder (e.g., polyvinylidene fluoride), such as: the material of the coating consists of 90% of lithium titanate, 5% of conductive carbon black and 5% of polyvinylidene fluoride according to mass percentage, wherein the conductive carbon black and oxygen react chemically at high temperature, and the binder is easy to remove at high temperature. Therefore, in step S4, the third mixture is subjected to the calcination treatment in the atmosphere containing oxygen (oxygen atmosphere or air atmosphere), so that the conductive carbon black and the binder can be effectively removed, thereby improving the purity of the recovered lithium titanate material.
In order to further improve the removal rate of impurities (conductive carbon black and binder) and to maintain the spherical structure of lithium titanate, in some embodiments of the present application, the calcination treatment is performed at a pressure of 0.2Mpa to 0.6Mpa, for example, values of 0.2Mpa, 0.3Mpa, 0.4Mpa, 0.5Mpa, 0.6Mpa, and any two of the foregoing numerical times.
In order to further compromise the improvement in the removal rate of impurities (conductive carbon black and binder) and the reduction in the hardening rate of the resulting lithium titanate material, in some embodiments of the present application, the calcination treatment is performed at a temperature of 550 ℃ to 760 ℃, such as 550 ℃, 600 ℃, 650 ℃, 700 ℃, 760 ℃, and values between any two of the foregoing values.
In order to enhance the quality of the recovered lithium titanate material, in some embodiments of the present application, the quality of the third mixture is 100g to 300g, which may be, for example, 100g, 200g, 300g, and values between any two of the foregoing; the calcination treatment time is 1h to 4h, and may be, for example, 1h, 2h, 3h, 4h, or any value between any two of the foregoing values.
In order to promote the uniformity of the size of the recovered lithium titanate material, in some embodiments of the present application, for step S4, after the step of calcining, and before the step of obtaining the lithium titanate material, the recycling method further comprises the steps of: the material obtained after the sintering treatment is sieved with a sieve, wherein the mesh number of the sieve is 200 mesh, for example. The material passing through the screen mesh is the recovered lithium titanate material.
The embodiment of the application also provides a lithium titanate material which is recovered by adopting the recycling method according to any one of the above.
Specifically, the lithium titanate material has a spherical structure.
In some embodiments of the present application, the first charge capacity of the lithium titanate material under the condition of 1C of electricity buckling is 130mAh/g to 160mAh/g, and/or the first discharge capacity of the lithium titanate material under the condition of 1C of electricity buckling is 130mAh/g to 160mAh/g, and/or the first charge-discharge efficiency of the lithium titanate material under the condition of 1C of electricity buckling is greater than 98%.
The embodiment of the application also provides a recycling method as described in any one of the above, or application of the lithium titanate material as described in any one of the above in preparation of the lithium titanate battery. Specifically, the lithium titanate material obtained by recycling any one of the above methods or the lithium titanate material used for preparing the negative electrode sheet of the lithium titanate battery and/or the electrode current collector obtained by recycling any one of the above methods are used for preparing the negative electrode sheet of the lithium titanate battery.
The embodiment of the application also provides a lithium titanate battery, which comprises a lithium titanate negative electrode plate, wherein the lithium titanate negative electrode plate comprises a negative electrode current collector and a second coating coated on the negative electrode current collector, and the material of the second coating comprises any one of the lithium titanate materials recovered by the recycling method or any one of the lithium titanate materials recovered by the recycling method, and/or the negative electrode current collector is the electrode current collector recovered by any one of the recycling method.
The technical solutions and technical effects of the present application are described in detail below by means of specific embodiments, which are only some of the embodiments of the present application, and are not specifically limited to the present application.
Example 1
The embodiment provides a recycling method of a waste lithium titanate electrode slice and a recycled lithium titanate material. In the recycling method in this embodiment, the waste lithium titanate negative electrode sheet is used as a recycling object, the waste lithium titanate negative electrode sheet includes a negative electrode current collector and a first coating coated on the negative electrode current collector, the negative electrode current collector is made of aluminum foil, and the first coating is made of 90% of lithium titanate, 5% of conductive carbon black and 5% of polyvinylidene fluoride according to mass percentage.
The recycling method of the waste lithium titanate electrode slice comprises the following steps:
s1.1, taking 1.5kg of lithium titanate negative electrode plate, cutting the lithium titanate negative electrode plate into a plurality of square blocks with the size of 10cm multiplied by 10cm, placing the square blocks into a reaction kettle filled with 10L of deionized water, starting stirring at the stirring speed of 500r/min, and stirring for 2 hours to separate the lithium titanate from a negative electrode current collector, so as to obtain a first mixture containing the lithium titanate and the negative electrode current collector;
s1.2, placing the first mixture in a material barrel, enabling the first mixture to pass through a 200-mesh screen, enabling a second mixture (electrode slurry) containing lithium titanate to pass through the screen, and enabling the screen to intercept a negative electrode current collector so that the negative electrode current collector is recovered;
s1.3, carrying out suction filtration on the second mixture obtained in the step S1.2 to obtain a first filter cake; then, dispersing the first filter cake in deionized water for a first water washing treatment, and then carrying out suction filtration to remove water to obtain a second filter cake; then, dispersing the second filter cake in deionized water for a second water washing treatment, and then carrying out suction filtration to remove water to obtain a third filter cake; then, dispersing the third filter cake in deionized water to perform third water washing treatment, and then placing the material obtained after the third water washing treatment in a blast drying oven to be dried at the temperature of 120 ℃ to obtain a solid;
s1.4, crushing the solid obtained in the step S1.3 by adopting a high-speed crusher, then passing the material obtained after the crushing through a 200-mesh screen, and collecting the material passing through the screen, wherein the material passing through the screen is a third mixture;
s1.5, weighing 200g of a third mixture in a sagger, placing the sagger carrying the third mixture in a high-temperature atmosphere furnace, and calcining the third mixture in a compressed air atmosphere (the pressure is 0.4 MPa), wherein the calcining temperature is 700 ℃, the calcining time is 2 hours, and sieving the calcined material with a 200-mesh sieve; the material passing through the screen was subjected to X-ray diffraction analysis, as shown in fig. 2, and the material passing through the screen had good lithium titanate diffraction peaks and no significant impurity peaks appeared, indicating that the material passing through the screen was recovered lithium titanate material.
Morphology of the recovered lithium titanate material was observed using a scanning electron microscope (Scanning Electron Microscope, SEM), as shown in fig. 3, and the recovered lithium titanate material maintained a spherical structure, thereby illustrating: the lithium titanate in the lithium titanate pole piece is effectively recycled, and the structure of the lithium titanate is not damaged in the recycling process.
And preparing a CR2016 button cell by using the recovered lithium titanate material, standing for 8 hours, setting the current density of the cathode to be 1C after the open-circuit voltage is stable, performing charge-discharge test, wherein the charge cut-off voltage is 2.7V, and after standing for 1min, the discharge cut-off voltage is 1.5V, recording the first charge capacity and the first discharge capacity, and calculating the first charge-discharge efficiency, wherein the first discharge efficiency is the ratio of the first discharge capacity to the first charge capacity.
Five parallel samples were set up in total for testing and the test results are shown in table 1 below:
table 1 presents a list of the properties of the lithium titanate materials recovered in this example under the 1C conditions of the power-on
As can be seen from Table 1, the lithium titanate material recovered in this embodiment has a first charge capacity of 155.1mAh/g to 158.2mAh/g and a first discharge capacity of 155.5mAh/g to 158.6mAh/g under the condition of 1C of electricity buckling, and the first charge and discharge efficiency is 98.67% to 100.26%, which indicates that the lithium titanate material recovered in this embodiment has good charge and discharge performance and can be used for preparing lithium titanate batteries.
Example 2
The embodiment provides a recycling method of a waste lithium titanate electrode plate and a recycled lithium titanate material, and compared with the recycling method of the waste lithium titanate electrode plate in embodiment 1, the recycling method of the waste lithium titanate electrode plate in the embodiment is only different in that: the temperature of the calcination treatment in step S1.5 was replaced with "500 ℃.
The morphology of the calcined material was observed by a scanning electron microscope, and as shown in fig. 4, lithium titanate in the calcined material maintained a spherical structure, thereby explaining: the lithium titanate in the lithium titanate pole piece is effectively recycled, and the structure of the lithium titanate is not damaged in the recycling process.
In addition, the material after the calcination treatment is gray, and the analysis of the element types and the element contents of the material after the calcination treatment is carried out by an energy spectrometer (Energy Dispersive Spectrometer, EDS), and the detection shows that the material after the calcination treatment contains trace carbon, thereby indicating that: the calcination treatment temperature is low, and conductive carbon black remains in the material.
And preparing a CR2016 button cell by using the recovered lithium titanate material, standing for 8 hours, setting the current density of the cathode to be 1C after the open-circuit voltage is stable, performing charge-discharge test, wherein the charge cut-off voltage is 2.7V, and after standing for 1min, the discharge cut-off voltage is 1.5V, recording the first charge capacity and the first discharge capacity, and calculating the first charge-discharge efficiency, wherein the first discharge efficiency is the ratio of the first discharge capacity to the first charge capacity.
Five parallel samples were set up in total for testing and the test results are shown in table 2 below:
table 2 Table 1A Table 2 shows the performance of the lithium titanate materials recovered in this example under the 1C condition of power-down
As can be seen from Table 2, the lithium titanate material recovered in this example has a first charge capacity of 134.6mAh/g to 135.7mAh/g, a first discharge capacity of 134.2mAh/g to 135.0mAh/g, and a first charge/discharge efficiency of 99.7% to 100.2% under the condition of 1C of power-on.
The charge and discharge performance of the lithium titanate material recovered in this example was slightly inferior to that of the lithium titanate material recovered in example 1, because: the calcination treatment temperature is low, and the recovered lithium titanate material contains a trace amount of conductive carbon black, so that the purity of the recovered lithium titanate material in the embodiment is slightly lower than that of the recovered lithium titanate material in the embodiment 1.
Example 3
The embodiment provides a recycling method of a waste lithium titanate electrode plate and a recycled lithium titanate material, and compared with the recycling method of the waste lithium titanate electrode plate in embodiment 1, the recycling method of the waste lithium titanate electrode plate in the embodiment is only different in that: the temperature of the calcination treatment in step S1.5 was replaced with "800 ℃.
The morphology of the calcined material was observed by a scanning electron microscope, as shown in fig. 5, in which lithium titanate maintains a spherical structure, but cracks exist on the surface, probably due to the following reasons: the calcination treatment temperature is high.
And preparing a CR2016 button cell by using the recovered lithium titanate material, standing for 8 hours, setting the current density of the cathode to be 1C after the open-circuit voltage is stable, performing charge-discharge test, wherein the charge cut-off voltage is 2.7V, and after standing for 1min, the discharge cut-off voltage is 1.5V, recording the first charge capacity and the first discharge capacity, and calculating the first charge-discharge efficiency, wherein the first discharge efficiency is the ratio of the first discharge capacity to the first charge capacity.
Five parallel samples were set up in total for testing and the test results are shown in table 3 below:
table 3 presents a list of the properties of the lithium titanate materials recovered in this example under the 1C conditions of the power-down
As shown in Table 3, the lithium titanate material recovered in this example has a first charge capacity of 143.2mAh/g to 144.1mAh/g, a first discharge capacity of 142.3mAh/g to 143.6mAh/g, and a first charge/discharge efficiency of 99.3% to 99.8% under the condition of 1C of electricity.
The charge and discharge performance of the lithium titanate material recovered in this example was slightly inferior to that of the lithium titanate material recovered in example 1, because: the calcination treatment temperature is higher, and cracks exist on the surface of the recovered lithium titanate material, so that the electrochemical performance of the recovered lithium titanate material in the embodiment is slightly reduced compared with that of the recovered lithium titanate material in the embodiment 1.
Example 4
The embodiment provides a recycling method of a waste lithium titanate electrode plate and a recycled lithium titanate material, and compared with the recycling method of the waste lithium titanate electrode plate in embodiment 1, the recycling method of the waste lithium titanate electrode plate in the embodiment is only different in that: omitting step S1.4, placing 200g of the third mixture in a sagger in step S1.5, placing the sagger loaded with the third mixture in a high-temperature atmosphere furnace, calcining the third mixture under the atmosphere of compressed air (the pressure is 0.4 MPa), replacing with weighing 200g of the solid obtained in step S1.3, placing the sagger loaded with the solid in the sagger, and calcining the solid under the atmosphere of compressed air (the pressure is 0.4 MPa).
The material after the calcination treatment was visually observed, and black spots were found in the material, thereby indicating that: the solid obtained in the step S1.3 is directly calcined without crushing treatment, and the phenomenon of incomplete calcination exists.
And preparing a CR2016 button cell by using the recovered lithium titanate material, standing for 8 hours, setting the current density of the cathode to be 1C after the open-circuit voltage is stable, performing charge-discharge test, wherein the charge cut-off voltage is 2.7V, and after standing for 1min, the discharge cut-off voltage is 1.5V, recording the first charge capacity and the first discharge capacity, and calculating the first charge-discharge efficiency, wherein the first discharge efficiency is the ratio of the first discharge capacity to the first charge capacity.
Table 4 presents a list of the properties of the lithium titanate materials recovered in this example under the 1C conditions of the power-down
As shown in Table 4, the lithium titanate material recovered in this example has a first charge capacity of 136.8mAh/g to 137.9mAh/g, a first discharge capacity of 136.2mAh/g to 137.2mAh/g, and a first charge/discharge efficiency of 99.4% to 100.1% under the condition of 1C of electricity.
The charge and discharge performance of the lithium titanate material recovered in this example was slightly inferior to that of the lithium titanate material recovered in example 1, because: the solid obtained in step S1.3 is directly calcined without crushing treatment, and there is a phenomenon that calcination is not thorough, so that the recovered lithium titanate material contains a trace amount of conductive carbon black, and the purity of the recovered lithium titanate material in this example is slightly lower than that of the recovered lithium titanate material in example 1.
The recycling method of the waste lithium titanate electrode plate, the lithium titanate material and the application provided by the embodiment of the application are described in detail. The principles and embodiments of the present application are described herein with reference to specific examples, the description of which is only for aiding in understanding the technical solution of the present application and its core ideas; those of ordinary skill in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the scope of the corresponding technical solutions of the embodiments of the present application.
Claims (10)
1. The recycling method of the waste lithium titanate electrode plate is characterized by comprising the following steps of:
providing a lithium titanate electrode sheet, wherein the lithium titanate electrode sheet comprises an electrode current collector and a first coating coated on the electrode current collector, the material of the first coating comprises lithium titanate, and the lithium titanate is separated from the electrode current collector in a solution environment to obtain a first mixture comprising the lithium titanate and the electrode current collector;
removing and recovering the electrode current collector in the first mixture to obtain a second mixture comprising the lithium titanate;
performing solid-liquid separation on the second mixture to obtain a solid third mixture, wherein the third mixture comprises the lithium titanate; and
and calcining the third mixture in an atmosphere containing oxygen to obtain the lithium titanate material.
2. The recycling method according to claim 1, wherein the step of separating the lithium titanate from the electrode current collector in the environment of a solution comprises: placing the lithium titanate electrode sheet in the solution, and separating the lithium titanate from the electrode current collector under stirring; and/or
The solution is water.
3. The recycling method according to claim 1 or 2, characterized in that the removing and recycling of the electrode current collector in the first mixture includes the steps of: and filtering the first mixture to obtain a retentate which is the electrode current collector.
4. A recycling method according to claim 3, wherein the filtering of the first mixture comprises the steps of: filtering the first mixture with a 100 mesh to 300 mesh screen; wherein the lithium titanate in the first mixture passes through the mesh, the mesh trapping the electrode current collector.
5. The recycling method according to claim 1, wherein in the step of subjecting the second mixture to solid-liquid separation, the solid-liquid separation includes one or more of suction filtration, centrifugation, reverse osmosis, membrane filtration, nanofiltration, ultrafiltration, microfiltration, and gravity sedimentation.
6. The recycling method according to claim 1, characterized in that after the step of subjecting the second mixture to solid-liquid separation and before the step of obtaining a third mixture in solid state, the recycling method further comprises the steps of: collecting a first solid obtained through solid-liquid separation, performing one or more times of water washing treatment on the first solid, and then drying to obtain a second solid; the third mixture is the second solid;
alternatively, after the step of performing solid-liquid separation on the second mixture and before the step of obtaining a third mixture in a solid state, the recycling method further includes the steps of: collecting a first solid obtained through solid-liquid separation, and crushing the first solid to obtain a third solid with 50-300 meshes; the third mixture is the third solid;
alternatively, after the step of performing solid-liquid separation on the second mixture and before the step of obtaining a third mixture in a solid state, the recycling method further includes the steps of: collecting a first solid obtained through solid-liquid separation, performing one or more times of water washing treatment on the first solid, and then drying to obtain a second solid; crushing the second solid to obtain a fourth solid with 50-300 meshes; the third mixture is the fourth solid.
7. The recycling method according to claim 1, wherein the calcination treatment is performed under a pressure of 0.2Mpa to 0.6 Mpa; and/or
The temperature of the calcination treatment is 550-760 ℃; and/or
The mass of the third mixture is 100 g-300 g, and the calcination treatment time is 1 h-4 h.
8. A lithium titanate material, characterized by being recovered by the recovery method according to any one of claims 1 to 7.
9. The lithium titanate material of claim 8, wherein the lithium titanate material is of spherical structure; and/or
The first charge capacity of the lithium titanate material under the condition of 1C of electricity buckling is 130 mAh/g-160 mAh/g, and/or the first discharge capacity of the lithium titanate material under the condition of 1C of electricity buckling is 130 mAh/g-160 mAh/g, and/or the first charge-discharge efficiency of the lithium titanate material under the condition of 1C of electricity buckling is more than 98%.
10. Use of the recycling method according to any one of claims 1 to 7, or the lithium titanate material according to claim 8 or 9, in the preparation of lithium titanate batteries.
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