CN111900355A - Carbon cathode of lithium ion battery and preparation method and application thereof - Google Patents
Carbon cathode of lithium ion battery and preparation method and application thereof Download PDFInfo
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- CN111900355A CN111900355A CN202010786612.3A CN202010786612A CN111900355A CN 111900355 A CN111900355 A CN 111900355A CN 202010786612 A CN202010786612 A CN 202010786612A CN 111900355 A CN111900355 A CN 111900355A
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- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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Abstract
The invention relates to the technical field of battery cathodes, and provides a preparation method of a carbon cathode of a lithium ion battery, which comprises the following steps: mixing the lithium-embedded carbon material with MXene dispersion liquid to obtain mixed slurry; the mass ratio of the lithium intercalation carbon material to MXene, the particle size of the lithium intercalation carbon material, the lamella diameter of the MXene and the number of lamella layers are defined; and coating the obtained mixed slurry on a metal current collector, and drying to obtain the carbon cathode of the lithium ion battery. The method provided by the invention utilizes the principle of self-assembly film formation of the solvent evaporation nanosheet layer to construct a three-dimensional conductive network structure consisting of an MXene sheet layer and a lithium-embedded carbon material on a metal current collector. MXene is used as a conductive agent, a binder and an auxiliary active component, can replace a conventional high-molecular binder and a conventional conductive agent, can improve the conductivity of the electrode, and greatly improves the lithium storage performance of the electrode compared with a lithium-embedded carbon electrode prepared by a traditional method.
Description
Technical Field
The invention relates to the technical field of battery cathodes, in particular to a carbon cathode of a lithium ion battery and a preparation method and application thereof.
Background
The lithium ion battery as a clean and efficient energy storage device has the advantages of high energy density, long service life, good safety and the like, occupies the market of portable electronic equipment, and is widely applied to the fields of mobile phones, medical treatment, military equipment and the like. The carbon material has low cost, simple preparation process and environmental protection, is the most common lithium ion battery cathode material and realizes industrial production. In the traditional carbon electrode forming process, an insulating high-molecular binder (PVDF, CMC and the like) is used for bonding and forming a carbon material, and the carbon material is coated on a metal current collector, and in order to increase the conductivity of the electrode, 5-10 wt% of a conductive agent is generally additionally added. However, this electrode has significant disadvantages: on one hand, the high molecular binder (PVDF, CMC and the like) is an insulator, which can increase the internal resistance of an electrode and reduce the power density of a battery; on the other hand, the binder and the conductive agent are inactive components, which do not provide capacity, and are not beneficial to improving the energy density of the battery.
Transition metal carbide or nitride, MXene for short, is a novel two-dimensional material and is discovered for the first time in 2011. The composite material has the characteristics of high conductivity, good hydrophilicity and mechanical properties, and meanwhile, the composite material is flexible and adjustable in components and controllable in size, and shows great potential in the application aspect of electrode materials of secondary batteries and super capacitors. The two-dimensional lamellar structure of MXene has also received much attention in electrode formation. Due to the unique two-dimensional structure, the MXene solution can be used for preparing the flexible self-supporting membrane electrode in a vacuum filtration mode, can be directly applied to a secondary battery and a supercapacitor, and can also be used for preparing a supercapacitor electrode together with activated carbon. In the article MXene-bound Activated Carbon as a FlexibleElectron for High-Performance Supercapacitors (Lanyong Yu, Yury Gogotsi, BinXu, et al, ACS Energy Lett.2018,3, 1597-.
Therefore, the existing electrode preparation process is to form a film by vacuum filtration of a mixed solution, the size of the film electrode is limited by filtration equipment, the thickness of the film electrode is limited to a few micrometers to dozens of micrometers, the filtration time is too long, large-area electrodes cannot be continuously produced in batch, and the popularization and application of the electrodes are limited.
Disclosure of Invention
The invention aims to provide a lithium ion battery carbon negative electrode with excellent electrochemical performance, a preparation method and application thereof, and the preparation method can be used for continuously producing large-area lithium ion battery carbon negative electrodes in batch.
In order to achieve the above object, the present invention provides the following technical solutions:
a preparation method of a carbon cathode of a lithium ion battery comprises the following steps:
(1) mixing the lithium-embedded carbon material with MXene dispersion liquid to obtain mixed slurry; the mass ratio of the lithium-embedded carbon material to MXene in the MXene dispersion liquid is (5-19) to 1; the particle size of the lithium-embedded carbon material is 0.5-3 mu m; the diameter of the MXene sheet layer is 5-30 μm; the number of the MXene layers is 1-5;
(2) and (2) coating the mixed slurry obtained in the step (1) on a metal current collector, and drying to obtain the carbon cathode of the lithium ion battery.
Preferably, the lithium-intercalated carbon material in the step (1) comprises one or more of natural graphite, artificial graphite, hard carbon, soft carbon and mesocarbon microbeads.
Preferably, MXene in the step (1) comprises Ti3C2Tx、Ti2CTx、Ti2NTx、Ti3N2Tx、V2CTx、Mo2CTx、Nb2CTx、Nb4C3Tx、Cr2CTx、Mo2TiC2TxAnd Mo2Ti2C3TxOne or more of (a).
Preferably, the concentration of the MXene dispersion liquid in the step (1) is 1-20 mg/mL.
Preferably, the solvent of the MXene dispersion in step (1) comprises one or more of deionized water, dimethylformamide, N-methylpyrrolidone, isopropanol, ethanol, tetrahydrofuran and dimethyl sulfoxide.
Preferably, the coating in the step (2) includes casting, blade coating or extrusion coating.
Preferably, the metal current collector in the step (2) comprises copper foil or copper foam.
Preferably, the drying temperature in the step (2) is 25-120 ℃, and the drying time is 4-20 h.
The invention also provides the lithium ion battery carbon negative electrode prepared by the preparation method, which comprises a metal current collector, and a lithium-embedded carbon material and MXene attached to the surface of the metal current collector; the thickness of the metal current collector is 4-10 mu m; the thickness of the lithium-embedded carbon material and MXene attached to the surface of the metal current collector is 30-200 microns.
The invention also provides the application of the carbon cathode of the lithium ion battery in the technical scheme in the lithium ion battery, and the electrolytic liquid system of the lithium ion battery is that lithium hexafluorophosphate is dissolved in ester and ether solvents.
Has the advantages that:
the invention provides a preparation method of a carbon cathode of a lithium ion battery, which comprises the following steps: mixing the lithium-embedded carbon material with MXene dispersion liquid to obtain mixed slurry; the mass ratio of the lithium-embedded carbon material to MXene in the MXene dispersion liquid is (5-19) to 1; the particle size of the lithium-embedded carbon material is 0.5-3 mu m; the diameter of the MXene sheet layer is 5-30 μm; the number of the MXene layers is 1-5; and coating the obtained mixed slurry on a metal current collector, and drying to obtain the carbon cathode of the lithium ion battery. The method provided by the invention utilizes the principle of self-assembly film formation of the solvent evaporation nanosheet layer to construct a three-dimensional conductive network structure consisting of an MXene sheet layer and a lithium-embedded carbon material on a metal current collector. In the invention, MXene is used as a conductive agent, a binder and an auxiliary active component, can replace the conventional high-molecular binder and conductive agent, and can improve the conductivity of the electrode. The lithium-embedded carbon material is used as an active substance, and the specific capacity of the electrode can be improved by limiting the using amount and the particle size of the lithium-embedded carbon material. The invention limits the layer diameter and the layer number of the MXene layer to ensure that the MXene wraps the lithium-embedded carbon material to form a three-dimensional conductive network structure. The mass ratio of the lithium-embedded carbon material to MXene is (5-19): 1, so that the electrode has high specific capacity and excellent rate performance. Aiming at the defects of the polymer binder in the preparation of the activated carbon electrode, the lithium-embedded carbon material is used as the active material, and MXene is used as the conductive binder and the auxiliary active component, so that a three-dimensional conductive network structure formed by embedding the lithium-embedded carbon material between MXene sheet layers is formed, the transmission of electrons/ions can be promoted, and the power density of the battery can be improved; the addition of inactive components such as a binder and a conductive agent is avoided, and meanwhile, an additional lithium storage active site can be provided, which is beneficial to improving the energy density of the battery, so that the electrode has more excellent electrochemical performance than the traditional electrode taking a high molecular polymer as the binder. Experimental results show that the lithium storage capacity of the lithium ion battery carbon cathode with MXene as the multifunctional conductive binder is as high as 404.5mAh/g under the current density of 0.1C, and the lithium storage capacity of the hard carbon electrode with PVDF as the binder is only 360.3 mAh/g. Compared with the hard carbon electrode prepared by the traditional method, the lithium storage capacity of the electrode is remarkably improved by taking MXene as the multifunctional conductive adhesive.
The preparation method of the carbon cathode of the lithium ion battery provided by the invention is simple to operate, can prepare the large-area continuous carbon cathode of the lithium ion battery at one time according to actual needs, and has wide application prospect.
Drawings
FIG. 1 is a photograph of a mixed slurry after casting on a metallic current collector;
FIG. 2 is an SEM image of a carbon negative electrode of the lithium ion battery prepared in example 1;
FIG. 3 is a charge-discharge curve at 0.1C current density for a battery assembled with a carbon negative electrode of a lithium ion battery prepared in example 1;
FIG. 4 is an SEM image of a hard carbon electrode prepared by using PVDF as a binder in comparative example 1;
fig. 5 is a charge and discharge curve at a current density of 0.1C of the electrode-assembled battery prepared in comparative example 1;
FIG. 6 is a charge-discharge curve at 0.1C current density for a battery assembled from the carbon negative electrode of the lithium ion battery prepared in example 2;
fig. 7 is a charge-discharge curve at 0.1C current density for a battery assembled with a carbon negative electrode of a lithium ion battery prepared in example 3.
Detailed Description
The invention provides a preparation method of a carbon cathode of a lithium ion battery, which comprises the following steps:
(1) mixing the lithium-embedded carbon material with MXene dispersion liquid to obtain mixed slurry; the mass ratio of the lithium-embedded carbon material to MXene in the MXene dispersion liquid is (5-19) to 1; the particle size of the lithium-embedded carbon material is 0.5-3 mu m; the diameter of the MXene sheet layer is 5-30 μm; the number of the MXene layers is 1-5;
(2) and (2) coating the mixed slurry obtained in the step (1) on a metal current collector, and drying to obtain the carbon cathode of the lithium ion battery.
According to the invention, the lithium-embedded carbon material and MXene dispersion liquid are mixed to obtain mixed slurry.
In the invention, the particle size of the lithium-embedded carbon material is 0.5-3 μm, and preferably 1-2 μm. In the present invention, when the particle diameter of the lithium intercalation carbon material is preferably in the above range, the lithium intercalation carbon material can be wrapped by MXene sheets to form a three-dimensional conductive network, which can promote the electron/ion transport and improve the power density of the battery.
In the present invention, the lithium intercalation carbon material preferably includes one or more of natural graphite, artificial graphite, hard carbon, soft carbon, and mesocarbon microbeads (MCMB). The source of the lithium intercalation carbon material is not particularly limited in the present invention, and any commercially available product having the above particle size range, which is well known to those skilled in the art, may be used.
In the present invention, when the particle diameter of the lithium intercalation carbon material is not in the above range, the present invention preferably crushes the lithium intercalation carbon material so that the particle diameter of the lithium intercalation carbon material reaches the above particle diameter range. The operation of the crushing treatment in the present invention is not particularly limited, and the crushing treatment known to those skilled in the art may be used. In the present invention, the crushing preferably comprises ball milling.
In the invention, the layer diameter of MXene is 5-30 μm, preferably 10-25 μm, and more preferably 10-20 μm. In the invention, MXene is used as a conductive adhesive in a carbon cathode of a lithium ion battery to play a role of wrapping a lithium-embedded carbon material, and under the same quality, the larger the diameter of a sheet layer is, the more lithium-embedded carbon materials can be contacted, and the better the electrochemical performance is. In the invention, when the layer diameter of the MXene is in the range, the lithium-embedded carbon material with the particle size can be fully wrapped to form a three-dimensional conductive network, so that the transmission of electrons/ions can be promoted, and the power density of the battery can be improved.
In the invention, the number of the MXene layers is 1-5, preferably 1-3, and more preferably 1-2. In the invention, MXene is used as a conductive adhesive in a carbon cathode of a lithium ion battery to play a role in wrapping a lithium-embedded carbon material. In the invention, when the number of the MXene layers is within the range, the MXene layers can provide support for the lithium-embedded carbon material to form a three-dimensional conductive network, so that the transmission of electrons/ions can be promoted, and the power density of the battery can be improved.
In the invention, the mass ratio of the lithium-intercalated carbon material to MXene in the MXene dispersion liquid is (5-19): 1, preferably (8-17): 1, more preferably (10-15): 1. in the invention, MXene is used as a conductive adhesive and can wrap a lithium-embedded carbon material, and when the mass ratio of the lithium-embedded carbon material to the MXene is in the range, the electrochemical performance of the carbon negative electrode of the lithium ion battery can be ensured.
In the present invention, the MXene preferably comprises Ti3C2Tx、Ti2CTx、Ti2NTx、Ti3N2Tx、V2CTx、Mo2CTx、Nb2CTx、Nb4C3Tx、Cr2CTx、Mo2TiC2TxAnd Mo2Ti2C3TxOne or more of (a). In the invention, when MXene is the above-mentioned species, the electrochemical performance of the carbon negative electrode of the lithium ion battery can be further improved.
The preparation method of MXene is not particularly limited in the present invention, and a preparation method well known to those skilled in the art can be adopted. In the invention, the preparation method of MXene preferably comprises HF, LiF/HCl liquid phase etching or a high-temperature molten salt method. In the invention, when the MXene preparation method is preferably the method, MXene meeting the requirements can be further obtained, and the electrochemical performance of the carbon negative electrode of the lithium ion battery can be further improved.
In the present invention, the solvent of the MXene dispersion preferably includes one or more of deionized water, dimethylformamide, nitrogen methyl pyrrolidone, isopropanol, ethanol, tetrahydrofuran, and dimethyl sulfoxide. In the present invention, when the solvent is preferably the above-mentioned kind, the dispersion effect of the lithium intercalation carbon material and MXene can be further improved, and the electrochemical performance of the carbon negative electrode of the lithium ion battery can be further improved.
In the invention, the concentration of the MXene dispersion liquid is preferably 1-20 mg/mL, more preferably 5-15 mg/mL, and most preferably 10-15 mg/mL. In the invention, when the concentration of the MXene dispersion liquid is in the range, when the lithium intercalation carbon material is added according to the mass ratio of the lithium intercalation carbon material to the MXene, the obtained mixed slurry is more beneficial to uniformly coating on the current collector.
The operation of the mixing is not particularly limited, and the lithium-intercalated carbon material and the MXene dispersion liquid can be uniformly mixed by adopting a mixing mode well known to a person skilled in the art. In the present invention, the mixing is preferably ultrasonic or mechanical stirring.
In the invention, the stirring speed is preferably 500-800 r/min, more preferably 550-750 r/min, and most preferably 600-700 r/min; the stirring time is preferably 2-20 hours, and more preferably 5-10 hours.
In the invention, the power of the ultrasonic wave is preferably 150-500W, more preferably 200-350W, and most preferably 250-300W; the time of the ultrasonic treatment is preferably 0.5-2 h, and more preferably 1-2 h.
In the invention, when the parameters of stirring or ultrasound are preferably in the above ranges, the dispersing effect of MXene and lithium intercalation carbon materials in the mixed slurry can be further improved, which is more beneficial to obtaining a uniform electrode.
After the mixed slurry is obtained, the mixed slurry is coated on a metal current collector and dried to obtain the carbon cathode of the lithium ion battery.
In the present invention, the coating is preferably casting, blade coating or extrusion coating. The casting or doctor-blading operation is not particularly limited in the present invention, and may be performed in a manner known to those skilled in the art. In the present invention, when the coating is preferably performed in the above-described manner, uniform coating of the mixed slurry on the current collector can be further promoted, and a carbon negative electrode for a lithium ion battery having a smoother surface can be obtained.
In the present invention, the coating amount of the mixed slurry determines the area of the resulting electrode. In the present invention, when the concentration of the dispersion slurry is determined, an electrode of an arbitrary area can be obtained according to the difference in the coating amount without deteriorating the continuity of the electrode. In the invention, when the concentration of the dispersion slurry is 1-20 mg/mL, the mass ratio of the lithium intercalation carbon material to MXene in the MXene dispersion liquid is (5-19): 1, and the coating amount is preferably 10-20 mL, the area of the obtained carbon negative electrode of the lithium ion battery can reach 400cm2. The preparation method provided by the invention can break through the limitation of the traditional preparation process on the electrode area, and obtain the large-area lithium ion battery carbon cathode with good continuity.
In the present invention, the metal current collector preferably comprises copper foil or copper foam. The source of the copper foil or the copper foam is not particularly limited in the present invention, and a commercially available product known to those skilled in the art may be used. In the invention, when the copper foil or the foam copper is used as a metal current collector, the lithium ion battery carbon negative electrode with excellent electrochemical performance can be further obtained.
In the invention, the drying temperature is preferably 25-120 ℃, and more preferably 50-100 ℃; the drying time is preferably 4-20 hours, and more preferably 5-10 hours. In the present invention, when the drying parameter is preferably in the above range, the drying of the mixed slurry can be further promoted. The drying apparatus of the present invention is not particularly limited, and a drying apparatus known to those skilled in the art may be used. In the present invention, the drying device is preferably a vacuum drying oven.
The preparation method of the carbon cathode of the lithium ion battery provided by the invention takes a lithium-embedded carbon material as a main active material, and MXene as a conductive agent, a binder and an auxiliary active component. MXene is used as a multifunctional conductive adhesive to replace the traditional insulating polymer adhesive and conductive agent, so that the conductivity of the electrode can be improved; the lithium-embedded carbon material is embedded into a three-dimensional conductive network formed among MXene layers, so that the transmission of electrons/ions can be promoted, and the power density of the battery can be improved; the addition of inactive components such as a binder and a conductive agent is avoided, and meanwhile, an additional lithium storage active site can be provided, which is beneficial to improving the energy density of the battery, so that the electrode has more excellent electrochemical performance than the traditional electrode taking a high molecular polymer as the binder.
The invention also provides the lithium ion battery carbon cathode prepared by the preparation method in the technical scheme, which consists of two active components of a lithium-embedded carbon material and MXene and a metal current collector; the thickness of the metal current collector is 4-10 mu m; the thickness of the lithium-embedded carbon material and MXene attached to the surface of the metal current collector is 30-200 microns.
In the invention, the thickness of the lithium-embedded carbon material and MXene attached to the surface of the metal current collector is 30-200 μm, preferably 70-150 μm, and more preferably 70-100 μm. In the present invention, when the thicknesses of the lithium intercalation carbon material and MXene attached to the surface of the metal current collector are preferably within the above ranges, it is advantageous to improve the electrochemical performance of the carbon negative electrode of the lithium ion battery.
In the invention, the thickness of the metal current collector is 4-10 μm, preferably 4-8 μm, and more preferably 4-6 μm. In the invention, when the thickness of the metal current collector is preferably within the above range, the support can be provided for the lithium-embedded carbon material and MXene on the surface of the metal current collector, and the electrochemical performance of the carbon negative electrode of the lithium ion battery can be improved.
The lithium ion battery carbon negative electrode provided by the invention improves the proportion of the active substance lithium-embedded carbon material, and is beneficial to improving the specific capacity of the electrode; a small amount of MXene is used as a conductive adhesive, so that the use of a polymer adhesive which does not provide electric capacity is avoided, the problem of pore structure blockage caused by the polymer adhesive is also avoided, and the prepared carbon cathode of the lithium ion battery has excellent electrochemical performance.
The invention also provides the lithium ion battery carbon cathode obtained by the technical scheme and the application of the lithium ion battery carbon cathode in a lithium ion battery with an electrolyte system of lithium hexafluorophosphate dissolved in esters and ethers. The method for applying the carbon cathode of the lithium ion battery in the lithium ion battery with the electrolyte system that lithium hexafluorophosphate is dissolved in esters and ethers is not particularly limited, and the method for applying the electrode in the lithium ion battery, which is well known by the technical personnel in the field, can be adopted.
In the invention, the carbon cathode of the lithium ion battery has excellent electrochemical performance and excellent flexibility, and can be used for lithium ion batteries with electrolytic liquid systems in which lithium hexafluorophosphate is dissolved in ester and ether solvents.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Raw materials: hard charcoal with grain size of 0.5-1 μm; MXene dispersion: 10mg/mL of Ti3C2TxMXAn aqueous ene solution.
The preparation method comprises the following steps:
(1) adding 85mg of hard carbon particles into 1.5mL of MXene aqueous solution, stirring and mixing at a high speed of 600r/min for 15h, performing ultrasonic dispersion for 2h, and performing ultrasonic power of 500W to obtain mixed slurry;
(2) dropping the mixed slurry obtained in the step (1) onto a copper foil, and automatically casting on the liquid level; and (3) placing the substrate carrying the dispersion liquid in a vacuum oven, vacuumizing and drying at the temperature of 25 ℃ for 7h, then heating to 120 ℃ and drying for 6h to obtain the carbon cathode of the lithium ion battery (MXene: hard carbon: 15:85), and placing in a vacuum dryer for storage.
Fig. 1 is a photograph of a mixed slurry coated on a metal current collector after auto-casting;
fig. 2 is an SEM image of the carbon negative electrode of the lithium ion battery prepared in this example. From the right picture of fig. 2, it can be seen that the hard carbon particles are uniformly wrapped by the MXene sheets, and a good three-dimensional network is formed. From the left picture of fig. 2, it can be seen that the good three-dimensional network formed by the hard carbon particles wrapped by MXene is firmly attached to the copper foil.
And (3) electrochemical performance testing: cutting the obtained carbon cathode (shown by 'HC-MXene' legend) of the lithium ion battery into a circular sheet with the diameter of 10mm, using the circular sheet as a working electrode, using a lithium sheet as a counter electrode, and selecting a Celgard diaphragm and 1M LiPF6And (solvent EC/DMC ═ 1:1) electrolyte, assembling a button cell in a glove box, standing for 24h, and then performing electrochemical lithium storage performance test on a blue electric charge-discharge instrument.
Fig. 3 is a charge-discharge curve of the battery assembled by the carbon cathode of the lithium ion battery prepared in example 1 at a current density of 0.1C, and the lithium storage capacity can reach 404.5 mAh/g.
Comparative example 1
Uniformly mixing hard carbon, carbon black and PVDF according to a mass ratio of 85:10:5, adding an appropriate amount of NMP solution for wet grinding, coating the uniformly mixed slurry on a copper foil, drying, cutting into a pole piece with the diameter of 10mm, and drying at 120 ℃ for 6 hours under a vacuum condition to prepare a hard carbon negative electrode (shown by using a 'HC-PVDF' legend in the figure) with PVDF as a binder. The procedure for assembling the button cell in example 1 was followed for cell assembly and lithium storage performance testing.
FIG. 4 is an SEM image of a hard carbon electrode of comparative example 1 made with PVDF as the binder at 5000 magnification; as can be seen from fig. 4, a three-dimensional network structure is apparently not formed between the hard carbon particles, the carbon black and the PVDF.
Fig. 5 is a charge and discharge curve at a current density of 0.1C for the battery assembled with the electrode prepared in comparative example 1, and the lithium storage capacity is only 360.3 mAh/g.
As can be seen from fig. 3 and 5, the battery assembled by using the carbon negative electrode of the lithium ion battery prepared in example 1 of the present invention is much higher than the battery assembled by using the electrode prepared in comparative example 1 in terms of lithium storage capacity, which indicates that the preparation method provided by the present invention has excellent electrochemical properties compared to the carbon negative electrode of the lithium ion battery obtained by the conventional preparation method.
Example 2
Raw materials: graphite powder with the grain diameter of 1-2 mu m; MXene solution: 5mg/mL of Ti3N2TxMXene/Dimethylformamide (DMF) solution.
The preparation method comprises the following steps:
(1) adding 90mg of graphite powder particles into 2mL of MXene solution, stirring and mixing at a high speed of 450r/min for 10h, ultrasonically dispersing for 1h, and ultrasonically dispersing at the power of 350W to obtain mixed slurry;
(2) dropping the mixed slurry obtained in the step (1) onto a copper foil, and automatically casting on the liquid level; and (3) placing the substrate carrying the dispersion liquid in a vacuum oven, vacuumizing and drying at the temperature of 27.5 ℃ for 8h, then heating to 120 ℃ and drying for 6h to obtain the lithium ion battery carbon negative electrode (MXene: hard carbon: 10:90), and placing in a vacuum dryer for storage.
And (3) electrochemical performance testing: cutting the obtained carbon cathode (shown by GC-MXene) of the lithium ion battery into a circular sheet with the diameter of 10mm, using the circular sheet as a working electrode, using a lithium sheet as a counter electrode, and selecting a Celgard diaphragm and 1M LiPF6And (solvent EC/DMC ═ 1:1) electrolyte, assembling a button cell in a glove box, standing for 24h, and then performing electrochemical lithium storage performance test on a blue electric charge-discharge instrument.
Fig. 6 is a charge-discharge curve of a battery assembled by the carbon negative electrode of the lithium ion battery prepared in the embodiment at a current density of 0.1C, and the lithium storage capacity reaches 322.4 mAh/g.
Example 3
Raw materials: mesophase Carbon Microbeads (MCMB) with the particle size of 0.5-1.5 mu m; MXene solution: 1mg/mL Nb2CTxMXene/N-methylpyrrolidone (NMP) solution.
The preparation method comprises the following steps:
(1) adding 95mg of graphite powder particles into 5mL of MXene solution, stirring and mixing at a high speed of 300r/min for 5h, ultrasonically dispersing for 0.5h and ultrasonically dispersing at the power of 300W to obtain mixed slurry;
(2) dropping the mixed slurry obtained in the step (1) onto foam copper, and automatically casting on the liquid level; and (3) placing the substrate carrying the dispersion liquid in a vacuum oven, vacuumizing and drying at the temperature of 30 ℃ for 9h, then heating to 120 ℃ and drying for 6h to obtain the carbon cathode of the lithium ion battery (MXene: hard carbon: 5:95), and placing in a vacuum dryer for storage.
And (3) electrochemical performance testing: cutting the obtained carbon cathode (shown by 'MC-MXene' legend) of the lithium ion battery into a circular sheet with the diameter of 10mm, using the circular sheet as a working electrode, using a lithium sheet as a counter electrode, and selecting a Celgard diaphragm and 1M LiPF6And (solvent EC/DMC ═ 1:1) electrolyte, assembling a button cell in a glove box, standing for 24h, and then performing electrochemical lithium storage performance test on a blue electric charge-discharge instrument.
Fig. 7 is a charging and discharging curve of the battery assembled by the carbon cathode of the lithium ion battery prepared in the embodiment at a current density of 0.1C, and the lithium storage capacity is as high as 370.9 mAh/g.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A preparation method of a carbon cathode of a lithium ion battery comprises the following steps:
(1) mixing the lithium-embedded carbon material with MXene dispersion liquid to obtain mixed slurry; the mass ratio of the lithium-embedded carbon material to MXene in the MXene dispersion liquid is (5-19) to 1; the particle size of the lithium-embedded carbon material is 0.5-3 mu m; the diameter of the MXene sheet layer is 5-30 μm; the number of the MXene layers is 1-5;
(2) and (2) coating the mixed slurry obtained in the step (1) on a metal current collector, and drying to obtain the carbon cathode of the lithium ion battery.
2. The preparation method according to claim 1, wherein the lithium-intercalated carbon material in the step (1) comprises one or more of natural graphite, artificial graphite, hard carbon, soft carbon and mesocarbon microbeads.
3. The method according to claim 1, wherein MXene in the step (1) comprises Ti3C2Tx、Ti2CTx、Ti2NTx、Ti3N2Tx、V2CTx、Mo2CTx、Nb2CTx、Nb4C3Tx、Cr2CTx、Mo2TiC2TxAnd Mo2Ti2C3TxOne or more of (a).
4. The preparation method according to claim 1, wherein the concentration of MXene dispersion in step (1) is 1-20 mg/mL.
5. The preparation method according to claim 1, wherein the solvent of the MXene dispersion in step (1) comprises one or more of deionized water, dimethylformamide, N-methylpyrrolidone, isopropanol, ethanol, tetrahydrofuran and dimethyl sulfoxide.
6. The production method according to claim 1, wherein the coating in the step (2) includes casting, blade coating, or extrusion coating.
7. The method according to claim 1, wherein the metal current collector in the step (2) comprises copper foil or copper foam.
8. The preparation method according to claim 1, wherein the drying temperature in the step (2) is 25 to 120 ℃ and the drying time is 4 to 20 hours.
9. The carbon negative electrode of the lithium ion battery prepared by the preparation method of any one of claims 1 to 8, which comprises a metal current collector, and a lithium-embedded carbon material and MXene attached to the surface of the metal current collector; the thickness of the metal current collector is 4-10 mu m; the thickness of the lithium-embedded carbon material and MXene attached to the surface of the metal current collector is 30-200 microns.
10. The use of the carbon negative electrode of a lithium ion battery according to claim 9 in a lithium ion battery, wherein the electrolyte system of the lithium ion battery is a solution of lithium hexafluorophosphate in an ester or ether solvent.
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| CN114361386A (en) * | 2021-12-31 | 2022-04-15 | 惠州市豪鹏科技有限公司 | Pole piece, preparation method thereof and battery |
| CN114551888A (en) * | 2022-04-26 | 2022-05-27 | 北京三川烯能科技有限公司 | Method for inhibiting lithium precipitation of lithium ion battery negative electrode, slurry, negative electrode, battery and vehicle |
| CN114621633A (en) * | 2020-12-10 | 2022-06-14 | 中国科学院大连化学物理研究所 | Water-based MXene-based energy storage electrode material 3D printing ink, and preparation method and application thereof |
| CN114621636A (en) * | 2020-12-10 | 2022-06-14 | 中国科学院大连化学物理研究所 | Water-based MXene-based energy storage electrode material screen printing ink, and preparation method and application thereof |
| WO2023215818A3 (en) * | 2022-05-05 | 2023-12-28 | Drexel University | Battery cathodes containing mxenes processed from water-based slurries |
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| CN112928275B (en) * | 2021-01-27 | 2022-09-06 | 鸡西市唯大新材料科技有限公司 | Method for preparing lithium ion carbon negative electrode material by performing organic phosphorus modification on carbon black surface |
| CN113422112A (en) * | 2021-07-05 | 2021-09-21 | 大连理工大学 | High-energy and high-safety all-solid-state secondary battery based on lithium sulfide anode and preparation method thereof |
| CN114361386A (en) * | 2021-12-31 | 2022-04-15 | 惠州市豪鹏科技有限公司 | Pole piece, preparation method thereof and battery |
| CN114361386B (en) * | 2021-12-31 | 2024-01-23 | 惠州市豪鹏科技有限公司 | Pole piece, preparation method thereof and battery |
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