CN115000373A - Preparation method of lithium titanate/graphite composite negative electrode material - Google Patents
Preparation method of lithium titanate/graphite composite negative electrode material Download PDFInfo
- Publication number
- CN115000373A CN115000373A CN202210644661.2A CN202210644661A CN115000373A CN 115000373 A CN115000373 A CN 115000373A CN 202210644661 A CN202210644661 A CN 202210644661A CN 115000373 A CN115000373 A CN 115000373A
- Authority
- CN
- China
- Prior art keywords
- lithium titanate
- graphite
- negative electrode
- electrode material
- heat preservation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 108
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 83
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 82
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 77
- 239000002131 composite material Substances 0.000 title claims abstract description 72
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 70
- 239000010439 graphite Substances 0.000 title claims abstract description 70
- 239000007773 negative electrode material Substances 0.000 title claims abstract description 48
- 238000002360 preparation method Methods 0.000 title claims abstract description 27
- 238000010438 heat treatment Methods 0.000 claims abstract description 47
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 34
- 238000004321 preservation Methods 0.000 claims abstract description 29
- 239000004594 Masterbatch (MB) Substances 0.000 claims abstract description 23
- 238000002156 mixing Methods 0.000 claims abstract description 19
- 238000005469 granulation Methods 0.000 claims abstract description 17
- 230000003179 granulation Effects 0.000 claims abstract description 17
- 150000001875 compounds Chemical class 0.000 claims abstract description 16
- 238000004898 kneading Methods 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 13
- 238000001816 cooling Methods 0.000 claims abstract description 12
- 238000001354 calcination Methods 0.000 claims abstract description 8
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 239000011261 inert gas Substances 0.000 claims abstract description 5
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 11
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 239000001307 helium Substances 0.000 claims description 4
- 229910052734 helium Inorganic materials 0.000 claims description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 claims description 2
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 2
- 229930006000 Sucrose Natural products 0.000 claims description 2
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 claims description 2
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 2
- 239000011280 coal tar Substances 0.000 claims description 2
- 239000008103 glucose Substances 0.000 claims description 2
- 229910021382 natural graphite Inorganic materials 0.000 claims description 2
- 229920001568 phenolic resin Polymers 0.000 claims description 2
- 239000005011 phenolic resin Substances 0.000 claims description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 2
- 229920003987 resole Polymers 0.000 claims description 2
- 239000005720 sucrose Substances 0.000 claims description 2
- 239000011295 pitch Substances 0.000 claims 2
- 239000007789 gas Substances 0.000 abstract description 11
- 239000000463 material Substances 0.000 abstract description 9
- 230000008569 process Effects 0.000 abstract description 4
- 239000007772 electrode material Substances 0.000 abstract description 2
- 238000009776 industrial production Methods 0.000 abstract description 2
- 229930000044 secondary metabolite Natural products 0.000 description 13
- 239000010426 asphalt Substances 0.000 description 11
- 238000003756 stirring Methods 0.000 description 10
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 229910001416 lithium ion Inorganic materials 0.000 description 8
- 238000007600 charging Methods 0.000 description 6
- 229910003481 amorphous carbon Inorganic materials 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 239000007770 graphite material Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 238000003763 carbonization Methods 0.000 description 3
- 239000010406 cathode material Substances 0.000 description 3
- 239000011247 coating layer Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000010405 anode material Substances 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- -1 polypropylene Polymers 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000000462 isostatic pressing Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011331 needle coke Substances 0.000 description 1
- 239000002006 petroleum coke Substances 0.000 description 1
- 239000011334 petroleum pitch coke Substances 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- H01M4/362—Composites
- H01M4/364—Composites as mixtures
-
- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention relates to the field of electrode materials, and discloses a preparation method of a lithium titanate/graphite composite negative electrode material, which comprises the following steps: (1) heating and kneading lithium titanate and a primary carbon source to prepare a primary compound; (2) vacuum mixing the primary compound, graphite and a secondary carbon source to prepare a secondary mixture; (3) performing vacuum heat preservation granulation on the secondary mixture to prepare a composite master batch, wherein the vacuum heat preservation granulation comprises first-stage heat preservation and second-stage heat preservation; (4) calcining the composite master batch at a high temperature in an inert gas atmosphere, and naturally cooling to room temperature to prepare a lithium titanate/graphite composite negative electrode material; according to the negative electrode material prepared by the preparation method, the lithium titanate and the graphite are mixed more uniformly, and the formed material structure is more compact, so that when the negative electrode material is applied to a battery, the quick charge rate is obviously improved, and the problem of gas generation is avoided; the preparation method provided by the application is simple in process, low in cost and suitable for industrial production.
Description
Technical Field
The invention relates to the field of electrode materials, in particular to a preparation method of a lithium titanate/graphite composite negative electrode material.
Background
The application of lithium ion batteries is becoming more and more widespread, and the demand for performance of the lithium ion batteries in various aspects is improved along with the application of the lithium ion batteries. The requirement of the conventional power automobile on the quick charging capacity is that the charging can be finished within 8-80% of SOC within 18 minutes. The demand for improving the rate capability of the battery is very urgent, the negative electrode material is one of the key factors for restricting the rate capability of the lithium ion battery, and a great deal of research on the aspect is already carried out at present, and great progress is also made, but still there is room for further improvement. The current method for improving the graphite rate performance can be mainly achieved by improving the transmission of ions in a solid phase, such as increasing the ion transmission direction, widening the ion transmission channel, shortening the ion transmission path and the like.
The publication No. CN112289986A discloses a preparation method of a high-magnification fast-charging graphite cathode material, which comprises the steps of carrying out coarse crushing and fine grinding on one or more of needle coke, petroleum coke and pitch coke, then carrying out spheroidizing shaping treatment, mixing the obtained product with a first carbon source, heating for surface coating, then carrying out high-temperature carbonization, and then carrying out high-temperature graphitization treatment to obtain artificial graphite powder; and mixing the obtained artificial graphite powder with a second carbon source, heating for surface coating, and then carbonizing at high temperature to obtain the high-rate quick-charging graphite cathode material. The graphite cathode material prepared by the method has the advantages of high charge-discharge multiplying power, large discharge capacity and good cycle performance, and the battery prepared by the method has excellent comprehensive performance, but the method has very limited promotion on the quick charge performance due to the limitation of the graphite material and the thickness of the coating layer, and the lithium titanate cathode has been paid attention to due to the excellent lithium ion transmission capacity and cycle performance of the lithium titanate cathode. But the application of the conductive material is limited by the poor conductivity and serious gas generation problem when the conductive material is used for preparing a battery.
At present, reports of composite use of graphite and lithium titanate exist, such as the publication number CN106876675B, which discloses a preparation method of a lithium titanate graphite composite negative electrode material for a lithium ion battery, lithium titanate is distributed in a three-dimensional conductive network formed by graphite by means of simple and easy mechanical mixing, isostatic pressing fusion, crushing spheroidization, high-temperature sintering and the like, so that excellent electrical contact between lithium titanate and graphite can be maintained, the rate capability and cycle performance of the obtained composite negative electrode material are obviously improved, and the composite negative electrode material can be used as a negative electrode material of the lithium ion battery. However, the method has many steps, and simple mechanical mixing is difficult to uniformly disperse lithium titanate and graphite, so that lithium titanate is easy to agglomerate, and an ideal structure is difficult to obtain.
Further, as disclosed in publication No. CN104091937B, a lithium titanate-coated surface-treated graphite negative electrode material, a preparation method and applications thereof are provided. The preparation method of the anode material comprises the following steps: (1) a surface treatment step of a graphite-based basic negative electrode material; (2) and (3) in-situ generation of a lithium titanate coating layer. Based on the surface of properly passivated graphite cathode particles, a layer of lithium titanate material is coated on the surface of graphite, so that the purposes of optimizing the internal environment of the battery and improving the service performance of the battery are achieved under the low-temperature or high-temperature use condition; however, the material prepared by the method cannot solve the problem of lithium titanate gas production.
The prior art has the following problems: the high-rate quick-charging graphite material has low battery rate performance due to the limitation of lithium ion conductivity of the graphite material and the thickness of a coating layer, and the lithium titanate and graphite are not uniformly dispersed in the preparation process of the lithium titanate graphite composite negative electrode material, so that the lithium titanate is easy to agglomerate, and the gas production problem of the lithium titanate negative electrode material is serious.
Disclosure of Invention
In order to overcome the problems of low battery rate performance, serious gas generation problem, complex preparation process, non-uniform dispersion of lithium titanate and graphite and easy agglomeration of lithium titanate in the lithium titanate/graphite composite negative electrode material in the prior art, the preparation method of the lithium titanate/graphite composite negative electrode material is provided.
The specific technical scheme of the invention is as follows:
a preparation method of a lithium titanate/graphite composite negative electrode material comprises the following steps:
(1) according to the mass ratio of 1: 0.02-0.5 heating and kneading lithium titanate and a primary carbon source to prepare a primary compound, wherein the kneading temperature is 50-150 ℃, and the kneading time is 1-3 hours;
(2) according to the mass ratio of 1: 4-100: 0.5-5, vacuum mixing the primary compound, graphite and a secondary carbon source to prepare a secondary mixture; mixing for 0.5-2 h;
(3) performing vacuum heat preservation granulation on the secondary mixture in the step (2) to prepare a composite master batch, wherein the vacuum heat preservation granulation comprises first-stage heat preservation and second-stage heat preservation, the first-stage heat preservation temperature is 200-500 ℃, the first-stage heat preservation time is 0.5-1 h, the second-stage heat preservation temperature is 600-800 ℃, and the second-stage heat preservation time is 1-3 h;
(4) and (4) calcining the composite master batch in the step (3) at a high temperature in an inert gas atmosphere, and naturally cooling to room temperature to prepare the lithium titanate/graphite composite anode material.
The preparation method comprises the steps of coating a primary carbon source on lithium titanate to form a primary compound, mixing the primary compound, graphite and a secondary carbon source, mixing, performing two-stage heat preservation granulation to prepare a composite master batch, and calcining the composite master batch at a high temperature to prepare the lithium titanate/graphite composite negative electrode material; the kneading temperature of the primary carbon source is 50-150 ℃, the primary carbon source on the lithium titanate is converted from a solid state into a liquid state at the temperature and coated on the lithium titanate, the primary carbon source is converted into a solid state after being cooled, a carbon source shell is formed on the surface of the lithium titanate, the secondary carbon source, the primary compound and graphite are mixed in vacuum, the secondary carbon source is high-viscosity viscous fluid and can be used as a primary mixture and a graphite adhesive, the particle size of the graphite is larger than that of the lithium titanate, in the mixing process, the lithium titanate can be filled in gaps between the graphite and the graphite, the secondary carbon source is filled in the gaps between the graphite and the lithium titanate, and the formed secondary compound is a compact structure without gaps.
In the second vacuum heat-preservation granulation stage, the first heat-preservation temperature is 200-500 ℃, the primary carbon source and the secondary carbon source start to be subjected to preliminary carbonization, the primary carbon source and the secondary carbon source are both in a melting state in the heat-preservation starting stage, the secondary carbon source is a high-viscosity viscous fluid, the secondary composite is not in a structural collapse state, but a compact structure of the secondary composite is maintained all the time, the secondary carbon source and the primary carbon source in the secondary composite gradually start to be carbonized in the continuous heat-preservation process, the content of amorphous carbon starts to increase, and a solid compact spherical structure is formed, the temperature of the spherical structure in the second heat-preservation stage is 600-800 ℃, more amorphous carbon is formed by intensifying the carbonization degree of the primary carbon source and the secondary carbon source in the secondary composite, and a fine void structure starts to be generated on the secondary heat-preservation stage, finally, the formed composite master batch is converted into an amorphous carbon sphere with micropores, and lithium titanate and graphite are embedded in the amorphous carbon sphere; and finally, carrying out high-temperature calcination to convert the primary carbon source and the secondary carbon source into amorphous carbon to prepare the lithium titanate/graphite composite negative electrode material.
The lithium titanate and the graphite in the lithium titanate/graphite composite negative electrode material structure prepared by the preparation process are mixed more uniformly, and the formed material structure is more compact, so that when the lithium titanate/graphite composite negative electrode material is applied to a battery, the quick charge rate is obviously improved, and the problem of gas generation is avoided.
Preferably, the particle size of the lithium titanate in the step (1) is 0.05 to 2 μm.
Preferably, the primary carbon source in step (1) is selected from one or more of low-temperature pitch, coal tar and resol.
Preferably, the graphite in the step (2) is one or more selected from artificial graphite, natural graphite and expanded graphite, and the particle size of the graphite is 5-20 μm.
Preferably, the secondary carbon source in the step (2) is one or more selected from glucose, citric acid, asphalt, polyvinylpyrrolidone, sucrose and phenolic resin, and the viscosity of the secondary carbon source is 50000-500000 cp.
Preferably, the temperature rise rate of the vacuum heat preservation granulation in the step (3) is 3-10 ℃/min.
Preferably, in the step (4), the calcining temperature is 800-1100 ℃, and the calcining time is 1-3 h.
Preferably, the inert gas in step (4) is selected from any one or more of helium, argon and nitrogen.
Compared with the prior art, the method has the following technical effects: (1) according to the negative electrode material prepared by the preparation method, the lithium titanate and the graphite are mixed more uniformly, and the formed material structure is more compact, so that when the negative electrode material is applied to a battery, the quick charge rate is obviously improved, and the problem of gas generation is avoided; (2) the preparation method provided by the application is simple in process, low in cost and suitable for industrial production.
Detailed Description
The present invention will be further described with reference to the following examples.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.
Example 1
(1) Adding lithium titanate and low-temperature asphalt into a kneader according to the mass ratio of 1:0.1, kneading at 120 ℃ for 2 hours to obtain a primary composite;
(2) sucking the primary compound, the artificial graphite and the asphalt into a VC mixer through a vacuum pumping pipeline according to the mass ratio of 5:95:5, and mixing for 30min to obtain a secondary compound;
(3) transferring the secondary compound into a granulation kettle through vacuum equipment, introducing helium gas, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, then heating to 700 ℃ at a heating rate of 5 ℃/min, preserving heat for 2h, and naturally cooling to obtain a composite master batch;
(4) transferring the composite master batch into a box-type furnace, heating to 1000 ℃ at a heating rate of 5 ℃/min, preserving heat for 2h, and then naturally cooling to prepare the lithium titanate/graphite composite negative electrode material.
Example 2
(1) Adding lithium titanate and low-temperature asphalt into a kneader according to the mass ratio of 1:0.1, kneading at 120 ℃ for 2 hours to obtain a primary composite;
(2) sucking the primary compound, the artificial graphite and the asphalt into a VC mixer according to the mass ratio of 2:98:5, and mixing for 30min to obtain a secondary compound;
(3) transferring the secondary compound into a granulation kettle through vacuum equipment, introducing helium gas, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 1h, heating to 700 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 2h, and naturally cooling to obtain a composite master batch;
(4) transferring the composite master batch into a box furnace, heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, and then naturally cooling to prepare the lithium titanate/graphite composite negative electrode material.
Example 3
(1) Adding lithium titanate and low-temperature asphalt into a kneader according to the mass ratio of 1:0.1, kneading at 120 ℃ for 2 hours to obtain a primary composite;
(2) sucking the primary compound, the artificial graphite and the asphalt into a VC mixer according to the mass ratio of 10:90:5, and mixing for 30min to obtain a secondary compound;
(3) transferring the secondary compound into a granulation kettle through vacuum equipment, introducing inert atmosphere, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 1h, heating to 700 ℃ at a heating rate of 5 ℃/min, and keeping the temperature for 2h to obtain a composite master batch;
(4) transferring the composite master batch into a box furnace, heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, and then naturally cooling to obtain the lithium titanate/graphite composite negative electrode material.
Example 4
(1) Adding lithium titanate and low-temperature asphalt into a kneading machine according to the mass ratio of 1:0.1, kneading at 120 ℃ for 2 hours to prepare a primary composite;
(2) sucking the secondary compound, the artificial graphite and the asphalt into a VC mixer according to the mass ratio of 20:80:5, and mixing for 30min to obtain a secondary compound;
(3) transferring the secondary compound into a granulation kettle through vacuum equipment, introducing inert atmosphere, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 1h, heating to 700 ℃ at a heating rate of 5 ℃/min, and keeping the temperature for 2h to obtain a composite master batch;
(4) transferring the composite master batch into a box furnace, heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, and then naturally cooling to prepare the lithium titanate/graphite composite negative electrode material.
Example 5
(1) Adding lithium titanate and a resin A into a kneader according to the mass ratio of 1:0.1, kneading at 120 ℃ for 2h to prepare a primary composite;
(2) sucking the secondary compound, the artificial graphite and the resin into a VC mixer through a vacuum-pumping pipeline according to the mass ratio of 5:95:5, and mixing for 30 minutes to obtain the secondary compound;
(3) transferring the secondary compound into a granulation kettle through vacuum equipment, introducing inert atmosphere, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 1h, heating to 700 ℃ at a heating rate of 5 ℃/min, and keeping the temperature for 2h to obtain a composite master batch;
(4) transferring the composite master batch into a box furnace, heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, and then naturally cooling to prepare the lithium titanate/graphite composite negative electrode material.
Comparative example 1
(1) According to the following steps of 100: 5, sucking the artificial graphite and the asphalt into a VC mixer through a vacuum-pumping pipeline, and mixing for 30min to prepare a kneaded compound;
(2) transferring the kneaded compound to a granulation kettle through vacuum equipment, introducing argon, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 1h, heating to 700 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 2h, and preparing a composite master batch;
(3) transferring the composite master batch into a box furnace, heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, and then naturally cooling to prepare the lithium titanate/graphite composite negative electrode material.
Comparative example 2
(1) According to the weight ratio of 5:95:5, sucking the lithium titanate, the artificial graphite and the asphalt into a VC mixer through a vacuum-pumping pipeline, and stirring for 30min to prepare a mixed compound;
(2) transferring the mixed compound into a granulation kettle through vacuum equipment, introducing inert atmosphere, stirring at a speed of 100r/min, heating to 300 ℃ at a heating rate of 3 ℃/min, keeping the temperature for 1h, heating to 700 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 2h, and preparing a composite master batch;
(3) transferring the composite master batch into a box furnace, heating to 1000 ℃ at the heating rate of 5 ℃/min, preserving the heat for 2h, and then naturally cooling to obtain the lithium titanate/graphite composite negative electrode material.
Preparing the lithium titanate/graphite composite negative electrode materials prepared in the embodiments 1-5 and the comparative examples 1-2 into negative electrode plates, preparing the negative electrode plates into button cells, and testing the electrochemical performance of the button cells;
the preparation method of the negative pole piece comprises the following steps: mixing the graphite/graphite composite negative electrode material prepared in the embodiment 1-3 with conductive carbon black, sodium carboxymethylcellulose (CMC) and Styrene Butadiene Rubber (SBR) according to the mass ratio of 90:5:2:3, and adding deionized water as a solvent for stirring; uniformly stirring, uniformly coating on a copper foil current collector by using coating equipment, baking for 24 hours in a vacuum drying oven at 90 ℃, then uniformly pressing by using a roll machine, and finally preparing a circular pole piece with the diameter of 14mm by using a sheet punching machine to prepare a negative pole piece;
the button cell comprises the following steps: a 2025 button cell is assembled by taking a metal lithium sheet as a positive electrode, a diaphragm as a polypropylene membrane (Celgard 2300), and electrolyte as a mixed solution of 1mol/L lithium hexafluorophosphate and vinyl carbonate and dimethyl carbonate in equal volume ratio in a vacuum glove box filled with high-purity nitrogen;
the following electrochemical performance tests were carried out,
1) all batteries are subjected to constant-current and constant-voltage capacity test at a rate of 0.1C;
2) the button cell prepared from the negative electrode material of each example and the comparative example is subjected to constant current charging at the current of 2.2C until the SOC is cut off at 100%, and the quick lithium charging and separating points of the material are analyzed through a dV/dQ curve;
3) button cells made of the negative electrode materials of each example and comparative example were subjected to a high rate (3C) test;
4) the button cell prepared from the negative electrode material of each example and the comparative example is subjected to charge and discharge tests at a multiplying power of 0.1C, the cell is disassembled after 20 circles, bubbles on a pole piece and a diaphragm are observed, and the results are recorded in a small amount, a large amount and a large amount. The voltage range is 0-2V. The test results are shown in table 1.
TABLE 1 Performance test Table
As shown in table 1, although some capacity is sacrificed, the fast charge and rate capability of the lithium titanate/graphite composite material are greatly improved compared to the pure graphite material, mainly due to the excellent ion conductivity of lithium titanate. As can be seen from the comparison between examples 1-5 and comparative example 1, under the condition of the same lithium titanate addition amount, the fast charge performance and rate capability of the lithium battery assembled by the negative electrode material prepared by the preparation method provided by the application are remarkably improved, and the gas production amount of the examples 1-5 is remarkably reduced compared with that of the comparative examples 1-2, which shows that the gas production amount of the lithium battery assembled by the negative electrode material prepared by the preparation method provided by the application is less, because the material structure of the application is more compact, a stable and compact SEI film can be formed on the surface of the material, through the examples 1-4, it can be seen that the rate capability of the lithium titanate/graphite composite material is increased along with the increase of the lithium titanate addition amount, and the fast charge lithium precipitation point is increased and then reduced, which may be because the lithium titanate is excessive, and part of the lithium titanate forms an agglomerate in the composite material, the conductivity of the material is weakened, and in addition, the capacity of the composite material is reduced along with the increase of the addition amount of the lithium titanate, so that a proper matching proportion can be selected according to the requirement.
Claims (8)
1. A preparation method of a lithium titanate/graphite composite negative electrode material is characterized by comprising the following steps:
(1) according to the mass ratio of 1: 0.02-0.5 heating and kneading lithium titanate and a primary carbon source to prepare a primary compound, wherein the kneading temperature is 50-150 ℃, and the kneading time is 1-3 hours;
(2) according to the mass ratio of 1: 4-100: 0.5-5, vacuum mixing the primary compound, graphite and a secondary carbon source to prepare a secondary mixture; mixing for 0.5-2 h;
(3) performing vacuum heat preservation granulation on the secondary mixture in the step (2) to prepare a composite master batch, wherein the vacuum heat preservation granulation comprises first-stage heat preservation and second-stage heat preservation, the first-stage heat preservation temperature is 200-500 ℃, the first-stage heat preservation time is 0.5-1 h, the second-stage heat preservation temperature is 600-800 ℃, and the second-stage heat preservation time is 1-3 h;
(4) and (4) calcining the composite master batch obtained in the step (3) at a high temperature in an inert gas atmosphere, and naturally cooling to room temperature to obtain the lithium titanate/graphite composite negative electrode material.
2. The preparation method of the lithium titanate/graphite composite negative electrode material as claimed in claim 1, wherein the particle size of the lithium titanate in the step (1) is 0.05-2 μm.
3. The preparation method of the lithium titanate/graphite composite negative electrode material as claimed in claim 2, wherein the primary carbon source in the step (1) is selected from one or more of low-temperature pitch, coal tar and resol.
4. The preparation method of the lithium titanate/graphite composite negative electrode material as claimed in claim 2, wherein the graphite in the step (2) is selected from one or more of artificial graphite, natural graphite and expanded graphite, and the particle size of the graphite is 5-20 μm.
5. The method for preparing a lithium titanate/graphite composite negative electrode material as claimed in claim 2, wherein the secondary carbon source in the step (2) is one or more selected from glucose, citric acid, pitch, polyvinylpyrrolidone, sucrose and phenolic resin, and the viscosity of the secondary carbon source is 50000-500000 cp.
6. The preparation method of the lithium titanate/graphite composite negative electrode material as claimed in claim 1, wherein the temperature rise rate of the vacuum heat preservation granulation in the step (3) is 3-10 ℃/min.
7. The preparation method of the lithium titanate/graphite composite negative electrode material as claimed in claim 1, wherein in the step (4), the calcination temperature is 800-1100 ℃ and the calcination time is 1-3 h.
8. The method for preparing the lithium titanate/graphite composite negative electrode material as claimed in claim 1, wherein the inert gas in the step (4) is one or more selected from helium, argon and nitrogen.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210644661.2A CN115000373A (en) | 2022-06-08 | 2022-06-08 | Preparation method of lithium titanate/graphite composite negative electrode material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210644661.2A CN115000373A (en) | 2022-06-08 | 2022-06-08 | Preparation method of lithium titanate/graphite composite negative electrode material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115000373A true CN115000373A (en) | 2022-09-02 |
Family
ID=83033601
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210644661.2A Pending CN115000373A (en) | 2022-06-08 | 2022-06-08 | Preparation method of lithium titanate/graphite composite negative electrode material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115000373A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104916825A (en) * | 2015-06-26 | 2015-09-16 | 田东 | Preparation method of lithium battery high-voltage modified cathode material |
| CN105406046A (en) * | 2015-12-21 | 2016-03-16 | 深圳市金润能源材料有限公司 | Lithium titanate negative electrode material and preparing method of lithium titanate negative electrode material |
| WO2016042386A1 (en) * | 2014-09-19 | 2016-03-24 | Toyota Jidosha Kabushiki Kaisha | Secondary battery and method of manufacturing the same |
| CN106876675A (en) * | 2017-03-23 | 2017-06-20 | 福建翔丰华新能源材料有限公司 | A kind of lithium ion battery preparation method of lithium titanate composite cathode material of silicon/carbon/graphite |
| CN107316992A (en) * | 2017-05-27 | 2017-11-03 | 广东烛光新能源科技有限公司 | Lithium titanate anode material and preparation method thereof |
| CN108199011A (en) * | 2017-11-20 | 2018-06-22 | 深圳市斯诺实业发展股份有限公司 | A kind of preparation method of lithium titanate anode material |
| CN111333064A (en) * | 2020-03-25 | 2020-06-26 | 江西正拓新能源科技股份有限公司 | High-performance lithium ion battery graphite negative electrode material and preparation method thereof |
| CN111653739A (en) * | 2020-04-28 | 2020-09-11 | 万向一二三股份公司 | Method for preparing high-cycle-performance SiO negative electrode material of lithium battery |
-
2022
- 2022-06-08 CN CN202210644661.2A patent/CN115000373A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016042386A1 (en) * | 2014-09-19 | 2016-03-24 | Toyota Jidosha Kabushiki Kaisha | Secondary battery and method of manufacturing the same |
| CN104916825A (en) * | 2015-06-26 | 2015-09-16 | 田东 | Preparation method of lithium battery high-voltage modified cathode material |
| CN105406046A (en) * | 2015-12-21 | 2016-03-16 | 深圳市金润能源材料有限公司 | Lithium titanate negative electrode material and preparing method of lithium titanate negative electrode material |
| CN106876675A (en) * | 2017-03-23 | 2017-06-20 | 福建翔丰华新能源材料有限公司 | A kind of lithium ion battery preparation method of lithium titanate composite cathode material of silicon/carbon/graphite |
| CN107316992A (en) * | 2017-05-27 | 2017-11-03 | 广东烛光新能源科技有限公司 | Lithium titanate anode material and preparation method thereof |
| CN108199011A (en) * | 2017-11-20 | 2018-06-22 | 深圳市斯诺实业发展股份有限公司 | A kind of preparation method of lithium titanate anode material |
| CN111333064A (en) * | 2020-03-25 | 2020-06-26 | 江西正拓新能源科技股份有限公司 | High-performance lithium ion battery graphite negative electrode material and preparation method thereof |
| CN111653739A (en) * | 2020-04-28 | 2020-09-11 | 万向一二三股份公司 | Method for preparing high-cycle-performance SiO negative electrode material of lithium battery |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107946576B (en) | High-rate graphite negative electrode material, preparation method thereof and lithium ion battery | |
| CN106848264A (en) | A kind of porous silicon oxide lithium ion battery negative material and preparation method thereof | |
| CN107026262B (en) | High-capacity spherical hard carbon negative electrode material coated with graphene on surface | |
| CN112133896B (en) | High-capacity graphite-silicon oxide composite material and preparation method and application thereof | |
| CN113213470A (en) | Artificial graphite secondary particle, coating agent, preparation method and application thereof | |
| WO2021077586A1 (en) | Silicon-oxygen particle for electrode material, preparation method therefor and use thereof | |
| CN111646466A (en) | High-capacity high-compaction fast-charging composite graphite negative electrode material and preparation method thereof | |
| CN111009647B (en) | Lithium borosilicate alloy cathode active material of lithium secondary battery, cathode, preparation and application thereof | |
| CN111653739B (en) | Method for preparing high-cycle-performance SiO negative electrode material of lithium battery | |
| CN113451561B (en) | Silicon-based composite material and preparation method and application thereof | |
| CN112582592B (en) | High-compaction and fast-filling artificial graphite material and preparation method thereof | |
| CN111276677B (en) | Preparation method of carbon nano material/amorphous carbon/silicon monoxide composite material | |
| WO2016169150A1 (en) | Method for graphite fine powder to be doped and used as negative electrode material | |
| CN111689500A (en) | Preparation method of low-expansibility SiO/graphite composite electrode material | |
| CN113113572B (en) | High-rate natural graphite-based composite material for lithium ion battery and preparation method and application thereof | |
| CN113206249B (en) | Lithium battery silicon-oxygen composite anode material with good electrochemical performance and preparation method thereof | |
| CN115010109B (en) | Preparation method of phenolic epoxy resin-based hard carbon material, hard carbon material and sodium ion battery | |
| CN112421002B (en) | High-capacity silicon-carbon material and preparation method thereof | |
| CN110993916B (en) | Composite graphite negative electrode material and preparation method thereof | |
| CN110600738B (en) | Method for preparing low-temperature lithium ion battery hard carbon negative electrode material | |
| CN115000373A (en) | Preparation method of lithium titanate/graphite composite negative electrode material | |
| CN109786722B (en) | Method for producing electrochemically active material | |
| CN107959007B (en) | Preparation method of graphene-silicon-coated lithium ion battery negative electrode material | |
| CN107658457B (en) | SiO for fused salt electrolysis2-Gc/C composite electrode and preparation method thereof | |
| CN114031081B (en) | Isotropic silicon-carbon negative electrode material and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |