CN116812922A - Method for preparing graphene conductive slurry by utilizing recycled secondary battery negative electrode - Google Patents
Method for preparing graphene conductive slurry by utilizing recycled secondary battery negative electrode Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 91
- 229910021389 graphene Inorganic materials 0.000 title claims abstract description 77
- 238000000034 method Methods 0.000 title claims abstract description 38
- 239000002002 slurry Substances 0.000 title claims abstract description 15
- 239000002253 acid Substances 0.000 claims abstract description 40
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000000843 powder Substances 0.000 claims abstract description 28
- 239000000725 suspension Substances 0.000 claims abstract description 26
- 238000005406 washing Methods 0.000 claims abstract description 23
- 239000007787 solid Substances 0.000 claims abstract description 17
- 238000001132 ultrasonic dispersion Methods 0.000 claims abstract description 16
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000004108 freeze drying Methods 0.000 claims abstract description 13
- 239000000463 material Substances 0.000 claims abstract description 11
- 238000007599 discharging Methods 0.000 claims abstract description 9
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 8
- 238000007873 sieving Methods 0.000 claims abstract description 8
- 239000002245 particle Substances 0.000 claims abstract description 5
- 238000001035 drying Methods 0.000 claims description 12
- 238000005554 pickling Methods 0.000 claims description 9
- 229910021382 natural graphite Inorganic materials 0.000 claims description 7
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 5
- 229910021385 hard carbon Inorganic materials 0.000 claims description 5
- 229910021384 soft carbon Inorganic materials 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 4
- 239000010405 anode material Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 239000002931 mesocarbon microbead Substances 0.000 claims description 2
- 239000002699 waste material Substances 0.000 abstract description 14
- 238000004064 recycling Methods 0.000 abstract description 4
- 239000010926 waste battery Substances 0.000 abstract description 2
- 238000007792 addition Methods 0.000 description 19
- 239000010410 layer Substances 0.000 description 16
- 239000007773 negative electrode material Substances 0.000 description 14
- 229910002804 graphite Inorganic materials 0.000 description 11
- 239000010439 graphite Substances 0.000 description 11
- 239000007774 positive electrode material Substances 0.000 description 7
- 238000011084 recovery Methods 0.000 description 7
- 239000002994 raw material Substances 0.000 description 6
- 239000003575 carbonaceous material Substances 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000009830 intercalation Methods 0.000 description 3
- 230000002687 intercalation Effects 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 239000004005 microsphere Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 238000001237 Raman spectrum Methods 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 239000006183 anode active material Substances 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000011889 copper foil Substances 0.000 description 2
- 239000012043 crude product Substances 0.000 description 2
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000005496 eutectics Effects 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000020477 pH reduction Effects 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000010793 electronic waste Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- AWKHTBXFNVGFRX-UHFFFAOYSA-K iron(2+);manganese(2+);phosphate Chemical compound [Mn+2].[Fe+2].[O-]P([O-])([O-])=O AWKHTBXFNVGFRX-UHFFFAOYSA-K 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000012286 potassium permanganate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
Classifications
-
- 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
Abstract
The invention discloses a method for preparing graphene conductive slurry by utilizing a recycled secondary battery negative electrode, which relates to the field of recycling of waste batteries, and comprises the following steps: (1) After discharging treatment is carried out on the recovered secondary battery, the negative electrode plate is disassembled and taken out, the negative electrode plate is mechanically crushed, pyrolyzed and peeled off, and the solid with the particle size D50 smaller than 15 microns is collected as negative electrode main powder after sieving; (2) Carrying out acid washing treatment on the negative electrode main powder, and keeping the temperature of the material of an acid washing system at 80-90 ℃ to obtain an upper-layer acid suspension; the acid used in the acid washing includes hydrochloric acid, nitric acid and hydrofluoric acid; (3) And performing freeze drying treatment on the acidified suspension to prepare graphene, and further performing ultrasonic dispersion to obtain graphene conductive slurry. The method has simple steps and realizes the high-value application of the waste secondary battery.
Description
Technical Field
The invention relates to the field of recycling of waste batteries, in particular to a method for preparing graphene conductive slurry by recycling a secondary battery negative electrode.
Background
Along with the acceleration of the modern process, the consumption of secondary batteries in the industries of global electronic products, electric automobiles and the like is continuously increased, and electronic waste generated by waste secondary batteries is also rapidly increased. The conventional landfill and incineration treatment of waste secondary batteries can cause environmental and safety problems, and the recovery of the secondary batteries is mainly focused on the recovery of transition metals such as cobalt, iron, manganese and the like of positive active substances and copper and aluminum of positive and negative current collectors at present, but the recovery technology and industry of negative graphite are not perfect. The green recovery process of the waste secondary battery is important for environmental protection and resource recovery and reutilization.
Graphene is a two-dimensional carbon material with single-atom thickness formed by periodically arranging carbon atoms (in a benzene ring structure), and is favored by the industry because of excellent electric conduction, heat conduction, mechanics and optical properties. At present, the main preparation method of graphene is an improved Hummer method, but the main preparation method has certain environmental pollution and raw material limitation, and specifically comprises the following two aspects: (1) The improved Hummer method for preparing the oxidized-reduced graphene, such as the Chinese patent document with the publication number of CN103708445A, CN110606481A, and the like, involve strong corrosive oxidants (such as potassium permanganate, sodium nitrate, sodium thiosulfate, concentrated sulfuric acid, concentrated nitric acid, potassium dichromate and the like), which are poor in use environment friendliness and difficult to control in the manufacturing process; (2) The raw materials used are single, for example, natural graphite or expanded graphite is selected as the raw material of the graphite.
The Chinese patent document with publication number of CN111384462A discloses a method for preparing graphene by recovering graphite from a negative electrode active material of a waste secondary battery, which comprises the following steps: (1) Disassembling, separating, soaking in solvent, cleaning and drying the waste secondary battery to obtain a crude product of the negative electrode carbon material; (2) Extracting and washing the crude product of the negative electrode carbon material with the eutectic solvent, and obtaining the negative electrode carbon material extracted with the eutectic solvent after magnetic stirring, ultrasonic vibration, filtering and drying; (3) And (3) preparing graphene by using the negative electrode carbon material in the step (2) as a raw material through a Hummers redox method.
The Chinese patent document with publication number of CN113131029A discloses a method for recycling regenerated graphene from a graphite negative electrode of a secondary battery, which comprises the following steps: taking out the graphite cathode of the secondary battery, putting the graphite cathode into the solution for pre-expansion, and separating the copper foil and the graphite dispersion solution after full reaction; and neutralizing, solid-liquid separating, acid washing and drying the graphite dispersion solution to obtain black graphite, and preparing graphene after the black graphite is subjected to strong acid intercalation, oxidant oxidation, hydrolysis, solid-liquid separating, acid washing, drying and expansion.
However, the method has the problems of complex steps, difficult raw material acquisition, high equipment requirement and the like.
Disclosure of Invention
The invention provides a method for preparing graphene conductive slurry by utilizing a recycled secondary battery negative electrode, which combines the failure characteristics (layered stripping, interlayer spacing increase, structural collapse and the like) of a negative electrode active material in the later period of the cycle of a waste secondary battery and a specific preparation process to enable graphene to be rapidly stripped from the recycled negative electrode material, has simple steps and realizes the high-value application of the waste secondary battery.
The technical scheme adopted is as follows:
a method for preparing graphene conductive paste by using a recycled secondary battery negative electrode, comprising the following steps:
(1) After discharging treatment is carried out on the recovered secondary battery, the negative electrode plate is disassembled and taken out, the negative electrode plate is mechanically crushed, pyrolyzed and peeled off, and the solid with the particle size D50 smaller than 15 microns is collected as negative electrode main powder after sieving;
(2) Carrying out acid washing treatment on the negative electrode main powder, and keeping the temperature of the material of an acid washing system at 80-90 ℃ to obtain an upper-layer acid suspension; the acid used in the acid washing includes hydrochloric acid, nitric acid and hydrofluoric acid;
(3) And (3) performing freeze-drying treatment on the acidized suspension obtained in the step (2) to obtain graphene, and further performing ultrasonic dispersion to obtain graphene conductive slurry.
Preferably, the recovered secondary battery is a waste secondary battery whose actual capacity falls below 80% of rated capacity, including lithium ion batteries, sodium ion batteries, and the like.
The main failures of the waste secondary battery in the latter period of cycle are the failure of the anode active material, the destruction of the solid electrolyte interface film (SEI film), or the loss of electrolyte. The negative electrode material such as natural graphite, artificial graphite, intermediate carbon microspheres, soft carbon, hard carbon and the like is peeled off by intercalation of electrolyte solvents (such as PC solvents), the peeled negative electrode material is a main source of multi-layer or oligowall graphene, and the surface of the negative electrode material is easily pulverized and peeled off due to volume change caused by the intercalation and deintercalation processes of lithium in each charge and discharge cycle, so that the negative electrode material in the later cycle of the waste secondary battery is easier to peel compared with the initial state, and the extraction of graphene is theoretically facilitated; furthermore, the invention adopts a specific process to crush, pyrolyze and strip the negative electrode plate, acidify and oxidize the negative electrode plate further, freeze-dry the negative electrode plate, and further separate the graphene under the condition of rapid contraction and expansion; finally, the graphene conductive paste is formed through ultrasonic dispersion, and can be used for secondary battery conductive materials, heat conducting materials and the like.
Preferably, in step (1), the recovered secondary battery is discharged to 2V or less, and the reversible lithium is deintercalated from the negative electrode into the positive electrode material while reducing the safety risk of the subsequent process.
Preferably, the negative electrode material in the recovered secondary battery comprises at least one of natural graphite, artificial graphite, mesocarbon microbeads, soft carbon and hard carbon. The method has better applicability, and the difficulty of stripping the graphene is that from easy to difficult: hard carbon > natural graphite > soft carbon > mesophase carbon microsphere > artificial graphite.
Preferably, the conditions of pyrolytic stripping are: air or nitrogen atmosphere, the temperature is 450-850 ℃ and the time is 4-6 h. When the temperature is too low, the binder (polymer such as SBR or PAA) in the negative electrode and the auxiliary agent (CMC) cannot be decomposed, the stripping effect cannot be achieved, when the temperature is too high, the energy consumption cost is increased, and meanwhile, the high-temperature metal is easy to oxidize, so that metal copper impurities are introduced.
In the step (2), the mass fraction of hydrochloric acid is 15-37%, the mass fraction of hydrofluoric acid is 20-50%, and the mass fraction of nitric acid is 30-90%; the dosage ratio of the negative electrode main powder to the hydrochloric acid to the hydrofluoric acid to the nitric acid is 1:0.3:0.2 to 0.8:0.2 to 0.5. Specifically, the amounts of the three acids are adjusted according to the kind and state of the anode material.
Preferably, the pickling time is 12-36 hours.
Preferably, the step of freeze-drying is specifically: the temperature of the acidified suspension is reduced to-40 to-85 ℃ within 24 hours; and then drying for 1-2 h at the vacuum degree of 13-26 Pa and the temperature of 25-45 ℃.
The agglomerated graphene obtained after freeze drying can be further dispersed by ultrasonic dispersion to meet the requirements of processing use and performance improvement, and in the step (3), graphene is added into water or N-methyl pyrrolidone to be subjected to ultrasonic dispersion to obtain graphene conductive slurry with the solid content of 0.5-55wt%; preferably, the power of ultrasonic dispersion is 500-1500W and the time is 0.5-2 h.
Preferably, in the graphene conductive paste obtained by the method, the number of graphene layers is less than or equal to 15, and the specific surface area is 200-500 m 2 And/g, the thickness of the single-layer graphene is less than or equal to 20nm, the size of a sheet layer is less than or equal to 15 mu m, and the powder resistance is less than or equal to 25mΩ & cm; excellent performance.
Compared with the prior art, the invention has the beneficial effects that:
(1) The method provided by the invention directly pulverizes the cathode sheet in the recovered secondary battery mechanically, then carries out pyrolysis stripping, does not need a separation step of the cathode materials such as copper foil and cathode active substances, and is simple in step and easy to operate.
(2) According to the method, the characteristics (layered stripping, interlayer spacing increase, structural collapse and the like) of the anode active material failure at the later stage of the cycle of the waste secondary battery are utilized, the recycled anode material is obtained after acidification and oxidation, freeze drying is carried out by combining with the expansion and contraction characteristics of the material, graphene is rapidly stripped, and finally the graphene conductive paste is prepared through ultrasonic dispersion. According to the invention, the efficiency of graphene recovery is improved by utilizing the synergistic effect of the raw materials of the waste secondary batteries and the specific process, and the high-valued application of the waste secondary batteries is realized; in the method, the recovery rate of the graphene is more than or equal to 40%, and the purity of the recovered graphene powder is more than or equal to 99.8%.
Drawings
Fig. 1 is an electron microscopic view of graphene obtained in example 2.
Fig. 2 is an electron microscopic image of graphene obtained in example 4.
Fig. 3 is a raman spectrum of graphene obtained in example l to example 6.
Detailed Description
The invention is further elucidated below in connection with the examples and the accompanying drawing. It is to be understood that these examples are for illustration of the invention only and are not intended to limit the scope of the invention. The methods of operation, under which specific conditions are not noted in the examples below, are generally in accordance with conventional conditions, or in accordance with the conditions recommended by the manufacturer.
The recovered secondary battery in the embodiment is purchased from enterprises of bidi, ningde times, high-lying families, new airlines and the like.
Example 1
(1) Discharging the recovered new sodium electricity (positive electrode material comprises layered oxide/negative electrode material comprises hard carbon) with the actual capacity reduced below 80% of rated capacity to 0V, dismantling and taking out the negative electrode plate, mechanically crushing the negative electrode plate, and then thermally decomposing and stripping the negative electrode plate, wherein the conditions of thermally decomposing and stripping are as follows: under the air atmosphere, the temperature is 550 ℃ and the time is 5.5 hours, and after passing through a 100-mesh sieve, collecting the solid with the particle size D50 less than 15 microns as the negative electrode main powder;
(2) Pickling the negative electrode main powder (proportion of mixed acid: 37% HCl,30% HF and 80% HNO) 3 The method comprises the steps of carrying out a first treatment on the surface of the When the corresponding negative electrode main powder is 1kg, the addition amount of hydrochloric acid is 0.3kg, the addition amount of HF is 0.5kg, and HNO is added 3 The addition amount of (2) is 0.2kg; the material temperature is kept at 80 ℃ during acid washing, and the acid washing time is 12 hours, so that an upper-layer acidified suspension is obtained;
(3) And (3) freeze-drying the acidified suspension, reducing the temperature of the upper layer of the acidified suspension to-45 ℃ within 10h, further drying at the vacuum degree of 20Pa and the temperature of 35 ℃ for 1.5h to prepare graphene, and further adding the graphene into N-methylpyrrolidone, and performing 500W ultrasonic dispersion for 0.5h to obtain the graphene conductive slurry with the solid content of 3 wt%.
Example 2
(1) Discharging the recovered lithium ion battery (the positive electrode material comprises lithium iron phosphate/the negative electrode material comprises artificial graphite) with the actual capacity reduced below 70% of the rated capacity to 1.5V, disassembling and taking out the negative electrode plate, mechanically crushing the negative electrode plate, and then thermally decomposing and stripping the negative electrode plate, wherein the conditions of thermally decomposing and stripping are as follows: under nitrogen atmosphere, the temperature is 750 ℃ and the time is 5 hours, and after sieving by a 100-mesh sieve, collecting solid with the particle size D50 less than 15 microns as negative electrode main powder;
(2) Pickling the negative electrode main powder (proportion of matched acid: 30% HCl,40% HF and 68% HNO) 3 The method comprises the steps of carrying out a first treatment on the surface of the When the corresponding cathode main powder is 1kg, the addition amount of hydrochloric acid is 0.3kg, the addition amount of HF is 0.2kg, and HNO is added 3 The addition amount of the acid is 0.5 kg), the material temperature is kept at 85 ℃ during acid washing, and the acid washing time is 12h, so that an upper-layer acidified suspension is obtained;
(3) And (3) freeze-drying the acidified suspension, reducing the temperature of the upper layer of the acidified suspension to-85 ℃ within 24 hours, further drying at the temperature of 45 ℃ and the vacuum degree of 10Pa for 1.5 hours to prepare graphene, further adding the graphene into N-methylpyrrolidone, and performing ultrasonic dispersion for 2 hours at 1500W to obtain the graphene conductive slurry with the solid content of 7 wt%.
Example 3
(1) Discharging the recovered NCM811 ternary lithium battery (the positive electrode material comprises layered oxide NCM 811/the negative electrode material comprises natural graphite) with the actual capacity reduced to below 90% of rated capacity to 1.5V, disassembling and taking out the negative electrode plate, mechanically crushing the negative electrode plate, and then thermally stripping the negative electrode plate, wherein the conditions of thermal stripping are as follows: under the air atmosphere, the temperature is 650 ℃ and the time is 4 hours, and after sieving with a 100-mesh sieve, collecting the solid with D50 less than 15 microns as the negative electrode main powder;
(2) Pickling the negative electrode main powder (proportion of matched acid: 30% HCl,40% HF and 68% HNO) 3 The method comprises the steps of carrying out a first treatment on the surface of the When the corresponding negative electrode main powder is 1kg, the addition amount of hydrochloric acid is 0.3kg, the addition amount of HF is 0.3kg, and HNO is added 3 The addition amount of the acid is 0.3 kg), the material temperature is kept at 80 ℃ during acid washing, and the acid washing time is 12h, so that an upper-layer acidified suspension is obtained;
(3) And (3) performing freeze drying treatment on the acidified suspension, reducing the temperature of the upper layer of the acidified suspension to-55 ℃ within 15h, further drying at the vacuum degree of 25Pa and the temperature of 35 ℃ for 1.5h to prepare graphene, and further adding the graphene into water for 800W ultrasonic dispersion for 1h to obtain the graphene conductive slurry with the solid content of 5 wt%.
Example 4
(1) Discharging the lithium cobalt oxide battery (positive electrode materials comprise lithium cobalt oxide/negative electrode materials comprise mesophase carbon microspheres) with the actual capacity reduced to below 80% of rated capacity to 1.7V, disassembling and taking out a negative electrode plate, mechanically crushing the negative electrode plate, and then thermally decomposing and stripping the negative electrode plate, wherein the conditions of thermally decomposing and stripping are as follows: nitrogen atmosphere, 700 ℃ for 6 hours, and collecting solid with D50 less than 15 microns as negative electrode main powder after sieving with a 100-mesh sieve;
(2) Pickling the negative electrode main powder (proportion of matched acid: 30% HCl,40% HF and 68% HNO) 3 The method comprises the steps of carrying out a first treatment on the surface of the When the corresponding negative electrode main powder is 1kg, the addition amount of hydrochloric acid is 0.3kg, the addition amount of HF is 0.3kg, and HNO is added 3 The addition amount of the acid is 0.4 kg), the material temperature is kept at 80 ℃ during acid washing, and the acid washing time is 12h, so that an upper-layer acidified suspension is obtained;
(3) And (3) freeze-drying the acidified suspension, reducing the temperature of the upper layer of the acidified suspension to-75 ℃ within 20h, further drying at the vacuum degree of 25Pa and the temperature of 35 ℃ for 1.5h to prepare graphene, and further adding the graphene into N-methylpyrrolidone, and performing 800W ultrasonic dispersion for 1h to obtain the graphene conductive slurry with the solid content of 5 wt%.
Example 5
(1) Discharging the power lithium manganate battery (the positive electrode material comprises spinel lithium manganate/the negative electrode material comprises soft carbon) with the actual capacity reduced to below 80% of rated capacity to 1.8V, disassembling and taking out the negative electrode plate, mechanically crushing the negative electrode plate, and then thermally decomposing and stripping the negative electrode plate, wherein the conditions of thermally decomposing and stripping are as follows: air atmosphere, temperature 650 ℃, time 5h, and collecting solid with D50 less than 15 microns as negative electrode main powder after sieving with a 100-mesh sieve;
(2) Pickling the negative electrode main powder (proportion of matched acid: 30% HCl,40% HF and 68% HNO) 3 The method comprises the steps of carrying out a first treatment on the surface of the When the corresponding negative electrode main powder is 1kg, the addition amount of hydrochloric acid is 0.3kg, the addition amount of HF is 0.25kg, and HNO is added 3 The addition amount of (2) is 0.5 kg), the temperature of the material is kept at 80 ℃ during the pickling, and the acid is obtainedThe washing time is 12 hours, and the upper layer acidification suspension is obtained;
(3) And (3) performing freeze drying treatment on the acidified suspension, reducing the temperature of the upper layer of the acidified suspension to-70 ℃ within 15h, further drying at the vacuum degree of 25Pa and the temperature of 45 ℃ for 1.5h to prepare graphene, and further adding the graphene into water for 1000W ultrasonic dispersion for 1h to obtain the graphene conductive slurry with the solid content of 5 wt%.
Example 6
(1) Discharging the power type manganese iron phosphate battery (the positive electrode material comprises olivine type manganese iron lithium phosphate/the negative electrode material comprises natural graphite and artificial graphite coincidence material) with the actual capacity reduced to below 80% of rated capacity to 1.8V, disassembling and taking out the negative electrode plate, mechanically crushing the negative electrode plate, and then thermally decomposing and stripping the negative electrode plate, wherein the conditions of thermally decomposing and stripping are as follows: air atmosphere, temperature 650 ℃, time 4.5h, and collecting solid with D50 less than 15 microns as negative electrode main powder after sieving with a 100-mesh sieve;
(2) Pickling the negative electrode main powder (proportion of matched acid: 30% HCl,40% HF and 68% HNO) 3 The method comprises the steps of carrying out a first treatment on the surface of the When the corresponding negative electrode main powder is 1kg, the addition amount of hydrochloric acid is 0.3kg, the addition amount of HF is 0.25kg, and HNO is added 3 The addition amount of the acid is 0.5 kg), the material temperature is kept at 80 ℃ during acid washing, and the acid washing time is 12h, so that an upper-layer acidified suspension is obtained;
(3) And (3) performing freeze drying treatment on the acidified suspension, reducing the temperature of the upper layer of the acidified suspension to-65 ℃ within 18h, further drying at the vacuum degree of 25Pa and the temperature of 45 ℃ for 1.5h to prepare graphene, and further adding the graphene into water for 1000W ultrasonic dispersion for 1h to obtain the graphene conductive slurry with the solid content of 5 wt%.
Sample analysis
Fig. 1 is an electron microscopic view of graphene obtained in example 2, in which a significant graphene sheet structure is observed; fig. 2 is an electron microscopic view of graphene obtained in example 4, in which a significant graphene sheet structure is observed; fig. 3 is a raman spectrum of graphene obtained in examples i to 6, in which the D peak and the G peak are closer to each other in 6 examples, and no obvious 2D peak is found, so that the specific graphene oxide structure can be obtained in examples 1 to 6.
Physical properties of graphene in the graphene conductive pastes obtained in examples 1 to 6 were tested, and the results are shown in table 1:
table 1 comparison of graphene physical properties for different examples
While the foregoing embodiments have been described in detail in connection with the embodiments of the invention, it should be understood that the foregoing embodiments are merely illustrative of the invention and are not intended to limit the invention, and any modifications, additions, substitutions and the like made within the principles of the invention are intended to be included within the scope of the invention.
Claims (9)
1. A method for preparing graphene conductive paste by utilizing a recycled secondary battery cathode, which is characterized by comprising the following steps:
(1) After discharging treatment is carried out on the recovered secondary battery, the negative electrode plate is disassembled and taken out, the negative electrode plate is mechanically crushed, pyrolyzed and peeled off, and the solid with the particle size D50 smaller than 15 microns is collected as negative electrode main powder after sieving;
(2) Carrying out acid washing treatment on the negative electrode main powder, and keeping the temperature of the material of an acid washing system at 80-90 ℃ to obtain an upper-layer acid suspension; the acid used in the acid washing includes hydrochloric acid, nitric acid and hydrofluoric acid;
(3) And (3) performing freeze-drying treatment on the acidized suspension obtained in the step (2) to obtain graphene, and further performing ultrasonic dispersion to obtain graphene conductive slurry.
2. The method for producing a graphene conductive paste using a negative electrode of a secondary battery according to claim 1, wherein in the step (1), the secondary battery is discharged to 2V or less.
3. The method for preparing graphene conductive paste by using the recycled secondary battery anode according to claim 1, wherein the recycled secondary battery anode material comprises at least one of natural graphite, artificial graphite, mesocarbon microbeads, soft carbon, and hard carbon.
4. The method for preparing graphene conductive paste using a recycled secondary battery anode according to claim 1, wherein the conditions for pyrolytic stripping are: air or nitrogen atmosphere, the temperature is 450-850 ℃ and the time is 4-6 h.
5. The method for preparing graphene conductive paste by utilizing the recycled secondary battery cathode according to claim 1, wherein in the step (2), the mass fraction of hydrochloric acid is 15% -37%, the mass fraction of hydrofluoric acid is 20% -50%, and the mass fraction of nitric acid is 30% -90%; the dosage ratio of the negative electrode main powder to the hydrochloric acid to the hydrofluoric acid to the nitric acid is 1:0.3:0.2 to 0.8:0.2 to 0.5.
6. The method for preparing graphene conductive paste by using a recycled secondary battery negative electrode according to claim 1, wherein the pickling time is 12-36 hours.
7. The method for preparing graphene conductive paste by using a recycled secondary battery anode according to claim 1, wherein the step of freeze-drying is specifically: the temperature of the acidified suspension is reduced to-40 to-85 ℃ within 24 hours; and then drying for 1-2 h at the vacuum degree of 13-26 Pa and the temperature of 25-45 ℃.
8. The method for preparing graphene conductive paste by using a recycled secondary battery negative electrode according to claim 1, wherein in the step (3), graphene is added into water or N-methylpyrrolidone, and is subjected to ultrasonic dispersion to obtain graphene conductive paste with a solid content of 0.5-55wt%.
9. The method for preparing graphene conductive paste by using a recycled secondary battery negative electrode according to claim 8, wherein the power of ultrasonic dispersion is 500-1500W for 0.5-2 h.
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| US20130089784A1 (en) * | 2011-10-05 | 2013-04-11 | Yu-Jeong Cho | Negative active material and lithium battery containing the negative active material |
| CN108659671A (en) * | 2018-05-14 | 2018-10-16 | 中科广化（重庆）新材料研究院有限公司 | A kind of lignin/graphene-based composite anti-corrosive coating and the preparation method and application thereof |
| CN114835109A (en) * | 2022-05-19 | 2022-08-02 | 清华大学 | Green recycling method for waste lithium battery graphite negative electrode and graphene |
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| US20130089784A1 (en) * | 2011-10-05 | 2013-04-11 | Yu-Jeong Cho | Negative active material and lithium battery containing the negative active material |
| CN108659671A (en) * | 2018-05-14 | 2018-10-16 | 中科广化（重庆）新材料研究院有限公司 | A kind of lignin/graphene-based composite anti-corrosive coating and the preparation method and application thereof |
| CN114835109A (en) * | 2022-05-19 | 2022-08-02 | 清华大学 | Green recycling method for waste lithium battery graphite negative electrode and graphene |
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