CN118263402B - High-crystallinity carbon nitride coated graphite negative electrode and preparation method and application thereof - Google Patents
High-crystallinity carbon nitride coated graphite negative electrode and preparation method and application thereof Download PDFInfo
- Publication number
- CN118263402B CN118263402B CN202410696060.5A CN202410696060A CN118263402B CN 118263402 B CN118263402 B CN 118263402B CN 202410696060 A CN202410696060 A CN 202410696060A CN 118263402 B CN118263402 B CN 118263402B
- Authority
- CN
- China
- Prior art keywords
- graphite
- negative electrode
- coated
- carbon nitride
- coated graphite
- 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.)
- Active
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 123
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 123
- 239000010439 graphite Substances 0.000 title claims abstract description 123
- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical compound N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 title claims abstract description 28
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- 239000006258 conductive agent Substances 0.000 claims abstract description 13
- 239000011230 binding agent Substances 0.000 claims abstract description 10
- 239000007773 negative electrode material Substances 0.000 claims abstract description 7
- 239000003960 organic solvent Substances 0.000 claims abstract description 7
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 26
- 239000000463 material Substances 0.000 claims description 22
- 238000000498 ball milling Methods 0.000 claims description 18
- 238000000576 coating method Methods 0.000 claims description 11
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 10
- 239000002243 precursor Substances 0.000 claims description 10
- 239000002033 PVDF binder Substances 0.000 claims description 9
- 239000011248 coating agent Substances 0.000 claims description 9
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 9
- 238000005245 sintering Methods 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 7
- 239000000084 colloidal system Substances 0.000 claims description 6
- 239000011267 electrode slurry Substances 0.000 claims description 6
- 229910052786 argon Inorganic materials 0.000 claims description 5
- 238000000227 grinding Methods 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 4
- 239000006245 Carbon black Super-P Substances 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 claims description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical group C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 238000007873 sieving Methods 0.000 claims description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 20
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 20
- 229910052744 lithium Inorganic materials 0.000 description 46
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 44
- 210000001787 dendrite Anatomy 0.000 description 9
- 239000011247 coating layer Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000000151 deposition Methods 0.000 description 7
- 239000010410 layer Substances 0.000 description 7
- 238000001556 precipitation Methods 0.000 description 7
- 238000001878 scanning electron micrograph Methods 0.000 description 7
- 230000008021 deposition Effects 0.000 description 5
- 239000007772 electrode material Substances 0.000 description 5
- 230000014759 maintenance of location Effects 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 238000009830 intercalation Methods 0.000 description 4
- 230000002687 intercalation Effects 0.000 description 4
- 238000004807 desolvation Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000003917 TEM image Methods 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 238000009831 deintercalation Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000007770 graphite material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 229910015872 LiNi0.8Co0.1Mn0.1O2 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 238000007614 solvation Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000004627 transmission electron microscopy Methods 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- 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
- H01M4/366—Composites as layered products
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
-
- 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
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Composite Materials (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention discloses a high-crystallinity carbon nitride coated graphite negative electrode, and a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The graphite negative electrode coated with the high-crystallinity carbon nitride comprises a current collector, wherein the current collector is uniformly coated with a graphite negative electrode material, the graphite negative electrode material comprises coated graphite, a binder, a conductive agent and an organic solvent, and the coated graphite is a uniform high-crystallinity polymerized carbon nitride layer coated on the surface of the graphite. The high-crystallinity carbon nitride coated graphite negative electrode, the preparation method and the application thereof can solve the problems of short service life and low capacity of the traditional graphite negative electrode battery.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a high-crystallinity carbon nitride coated graphite negative electrode, and a preparation method and application thereof.
Background
Along with the development and application of the lithium ion battery in the fields of electric vehicles and energy storage, the requirements on the energy density, the cycle life and the safety performance of the lithium ion battery are also higher and higher. Currently, the commercial lithium ion battery cathode is mainly a graphite carbon material, and due to the low lithium intercalation potential, metallic lithium is preferentially deposited on the surface of the graphite cathode in a dendrite form under some severe charging conditions (low temperature, high multiplying power and the like), which is called cathode lithium precipitation. The deposit of metal lithium is extremely uneven and unstable, which can lead to the loss of active lithium capacity and internal micro-short circuit, and can puncture the diaphragm to cause internal short circuit and thermal runaway of the battery, which is a main problem affecting the cycle life and the safety performance of the lithium ion battery.
The prior art focuses mainly on both electrolyte engineering and graphite surface cladding.
Electrolyte design is primarily concerned with the solvation structure of li+ which determines the desolvation energy and properties (e.g., composition and thickness) of the Solid Electrolyte Interphase (SEI). In addition, the surface properties of graphite also affect the desolvation energy of li+, so amorphous carbon coatings and metal/metal oxide coatings/doping have also been reported. These strategies can effectively improve the desolvation kinetics of li+ and facilitate the elimination of lithium dendrites. However, these strategies do not simultaneously increase the li+ diffusion rate in the bulk graphite particles, and therefore Li plating is still unavoidable under severe conditions. And the surface coating of graphite may reduce the first-ring coulombic efficiency of the lithium ion battery, thereby reducing its capacity.
The prior patent CN202410164297.9 discloses a preparation method of a coated electrode material, the coated electrode material and a lithium ion battery, and a uniform coating layer is formed on the surface of the electrode material through ball milling and drying, so that the stability of the electrochemical performance of the battery is improved, and the service life of the battery is prolonged. The above patent is to form a nitrogen carbide coating layer on the surface of NCM811, and the electrode material is used in a lithium sheet, and the use of the electrode material has limited effect of improving the service life of a lithium ion battery.
Disclosure of Invention
The invention aims to provide a high-crystallinity carbon nitride coated graphite negative electrode, and a preparation method and application thereof, and solves the problems of short service life and capacity retention rate of the existing graphite negative electrode battery.
In order to achieve the above purpose, the invention provides a high-crystallinity carbon nitride coated graphite negative electrode, which comprises a current collector, wherein the current collector is uniformly coated with a graphite negative electrode material, the graphite negative electrode material comprises coated graphite, a binder, a conductive agent and an organic solvent, and the coated graphite is a uniform high-crystallinity polymerized carbon nitride layer coated on the surface of the graphite.
Preferably, the current collector is copper and the organic solvent is anhydrous N-methylpyrrolidone NMP.
Preferably, the binder is polyvinylidene fluoride PVDF, and the mass of the binder is 10% of the mass of the coated graphite.
Preferably, the conductive agent is conductive carbon black Super P, and the mass of the conductive agent is 10% of the mass of the coated graphite.
The preparation method of the high-crystallinity carbon nitride coated graphite cathode comprises the following steps:
s1, dissolving PVDF in anhydrous N-methylpyrrolidone NMP to obtain clear colloid liquid;
S2, uniformly dispersing the conductive agent and the coated graphite in colloid liquid, and adding anhydrous N-methyl pyrrolidone (NMP) to adjust the viscosity of the mixed liquid to 4000-8000 cps so as to obtain graphite negative electrode slurry;
And S3, uniformly coating the graphite negative electrode slurry on the surface of a current collector, drying and rolling to obtain the graphite negative electrode.
Preferably, in the step S2, the preparation method of the coated graphite includes the following steps:
s21, adding a precursor material into an N-methylpyrrolidone (NMP) solvent, and uniformly mixing by using a refiner to obtain a solution;
the N-methyl pyrrolidone NMP solvent can reduce side reactions on the surfaces of particles and improve the solubility of the coating material.
S22, pouring the solution into a ball milling tank, and adding graphite into the ball milling tank for ball milling to obtain ball grinding materials;
S23, placing the ball-milling materials into an oven for drying, and sieving the ball-milling materials; and (3) placing the sieved powder into a tubular furnace for sintering under the protection of argon, wherein the sintering temperature is 500 ℃, and the sintering time is 1h, so as to obtain the coated graphite.
Preferably, in the step S21, the precursor material is dicyandiamide, and the concentration of the precursor material is 0.1mg/mL.
When the content of the precursor material is small, the coating layer is incomplete, and when the content is too large, the coating layer is too thick, the resistance is too large, and the electrochemical performance of the electrode is affected.
Preferably, in the step S22, the concentration of graphite is 1g/mL.
Preferably, in the step S3, the compacted density of the graphite negative electrode plate is 1.4g/cm 3-1.6g/cm3.
The graphite cathode coated with the high-crystallinity carbon nitride is applied to a soft-package battery.
The high-crystallinity carbon nitride coated graphite negative electrode and the preparation method and application thereof have the advantages and positive effects that:
1. According to the invention, the graphite surface is successfully coated with the uniform carbon nitride coating layer with high crystallinity, the coating layer improves the transmission rate of lithium ions and uniform flux of lithium ions, so that lithium ions can be uniformly deposited on the graphite negative electrode, the formation of lithium dendrites of the graphite negative electrode is avoided, and the safety performance and the service life of the battery are improved.
2. The high-crystallinity carbon nitride coating layer on the surface of the graphite negative electrode can also enable precipitated lithium to be reversibly deintercalated to the positive electrode, thereby reducing the capacity attenuation of the battery caused by lithium precipitation and greatly improving the service life and the capacity retention rate of the battery.
3. The preparation method of the graphite cathode is simple, low in cost and easy to realize large-scale production.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is an SEM image of coated graphite according to one embodiment of the present invention;
FIG. 2 is a TEM image of a coated graphite according to an embodiment of the present invention;
FIG. 3 is a plan view of a coated graphite according to an embodiment of the present invention;
FIG. 4 is a graph showing the distribution of C element of a coated graphite according to an embodiment of the present invention;
FIG. 5 is a graph showing the N element distribution of a coated graphite according to an embodiment of the present invention;
FIG. 6 is a SEM image of deposited lithium at 1C for a graphite anode according to an embodiment of the present invention;
FIG. 7 is a SEM image of a graphite anode under 1C conditions according to an embodiment of the present invention;
FIG. 8 is a SEM image of the deposited lithium of a comparative graphite anode of the present invention at 1C;
FIG. 9 is a SEM image of the lithium intercalation of a comparative graphite negative electrode of the present invention at 1C;
Fig. 10 is a graph showing the long cycle performance of the soft pack battery prepared in example one and comparative examples of the present invention at 2C constant current charge and discharge.
Detailed Description
The technical scheme of the invention is further described below through the attached drawings and the embodiments.
Example 1
The graphite negative electrode coated with the high-crystallinity carbon nitride comprises a current collector, wherein the current collector is uniformly coated with a graphite negative electrode material, the graphite negative electrode material comprises coated graphite, a binder, a conductive agent and an organic solvent, and the coated graphite is a uniform high-crystallinity polymerized carbon nitride layer coated on the surface of the graphite.
The current collector is copper, and the organic solvent is anhydrous N-methylpyrrolidone NMP.
The binder is polyvinylidene fluoride PVDF, and the mass of the binder is 10% of the mass of the coated graphite.
The conductive agent is conductive carbon black Super P, and the mass of the conductive agent is 10% of the mass of the coated graphite.
The preparation method of the high-crystallinity carbon nitride coated graphite cathode comprises the following steps:
S1, dissolving PVDF in anhydrous N-methylpyrrolidone NMP to obtain clear colloid liquid.
S2, uniformly dispersing the conductive agent and the coated graphite in colloid liquid, and adding anhydrous N-methyl pyrrolidone (NMP) to adjust the viscosity of the mixed liquid to 5000 cps, so as to obtain the graphite negative electrode slurry.
And S3, uniformly coating the graphite negative electrode slurry on the surface of a current collector, drying and rolling to obtain the graphite negative electrode.
The compacted density of the graphite negative electrode plate is 1.5g/cm 3.
The preparation method of the coated graphite comprises the following steps:
s21, adding the precursor material into an N-methyl pyrrolidone NMP solvent, and uniformly mixing by using a refiner to obtain a solution.
The precursor material is dicyandiamide, and the concentration of the precursor material is 0.1mg/mL.
The speed of the refiner was 2000rpm.
S22, pouring the solution into a ball milling tank, and adding graphite into the ball milling tank for ball milling to obtain the ball grinding material.
The concentration of graphite was 1g/mL.
The ball-material ratio in the ball milling tank is 10:1, the grinding balls are zirconia grinding balls with different radii of 0.5mm-5mm, and the ball milling time is 12 hours.
S23, placing the ball-milling materials into a 100 ℃ oven for drying, and sieving the ball-milling materials with a 150-mesh sieve; and (3) placing the sieved powder into a tubular furnace for sintering under the protection of argon, wherein the sintering temperature is 500 ℃, and the sintering time is 1h, so as to obtain the coated graphite.
The obtained coated graphite was observed by a scanning electron microscope, and an SEM picture of the coated graphite is shown in fig. 1. It can be seen that the above method was used to obtain a lamellar coated graphite. Transmission electron microscopy observation was performed on the coated graphite, and a TEM image of the coated graphite is shown in fig. 2. It can be seen that a uniform coating is obtained on the surface of the graphite material, and many lattice fringes exist on the surface of the coating, which indicate that the coating material has a relatively good crystallinity.
The energy spectrum analysis is carried out on the coated graphite, and the distribution diagrams of the surface scanning diagram, the C element and the N element are respectively shown in fig. 3, fig. 4 and fig. 5. It can be seen that the surface C, N of the coating is very uniformly distributed, indicating that the graphite surface is coated with a uniform high crystallinity polymeric carbon nitride layer.
The obtained graphite negative electrode was used as a positive electrode, a lithium sheet was used as a negative electrode, celgard 2325 was used as a separator, and a coin cell was assembled in a glove box filled with argon gas (CR 2025).
Subsequently, graphite Li half-cell testing was performed under two conditions:
(1) Depositing lithium: constant current charge and discharge is carried out for 10 circles, the current is 1C (1 C=340 mAh/g), the state of charge SOC is 130%, and the cut-off voltage of charging is 1.5V. SOC refers to the amount of charge, and normal battery SOC is generally 100% to be considered full of charge, so in order to explore the problem of 3d n@g suppressing lithium precipitation, charge is continued at soc=100% so that lithium is precipitated on the graphite surface, thereby characterizing the induced deposition effect of 3d n@g on precipitated lithium. Finally, the discharge is carried out again, the SOC is still 130%, and lithium is deposited on the graphite surface.
(2) Lithium intercalation and deintercalation: constant current charge and discharge is carried out for 10 circles, the current is 1C (1 C=340 mAh/g), the state of charge SOC is 130%, the SOC is 130% after the last discharge, then lithium is extracted at the current of 0.1C, and the cut-off voltage is 1.5V.
SEM images of deposited lithium and deintercalated lithium of the graphite anode under 1C condition are shown in fig. 6 and 7, respectively. It can be seen that the coated graphite can induce the precipitated lithium to be uniformly deposited when the lithium ion battery graphite cathode is subjected to lithium precipitation, so that a uniform and compact lithium metal layer is formed, and no lithium dendrite is generated. The high-crystallinity carbon nitride coated on the surface of the graphite can be uniformly coated on the surface of the graphite, and meanwhile, the high-crystallinity carbon nitride on the surface can be used for uniformly transferring flux of lithium ions, so that the transfer rate of the lithium ions can be improved, the lithium ions can be induced to be uniformly deposited in a lithium precipitation state, and lithium dendrites formed by local aggregation deposition of the lithium ions are avoided. After the lithium ions are deintercalated in the graphite cathode, the graphite cathode still maintains a uniform lithium deposition layer, and lithium dendrites are not formed.
Comparative example
The preparation process and parameters of the graphite pole piece are the same as those of the first embodiment.
The obtained graphite negative electrode was used as a positive electrode, a lithium sheet was used as a negative electrode, celgard 2325 was used as a separator, and a coin cell was assembled in a glove box filled with argon gas (CR 2025).
Subsequently, graphite Li half-cell testing was performed under two conditions:
(1) Depositing lithium: constant current charge and discharge is carried out for 10 circles, the current is 1C (1 C=340 mAh/g), the state of charge SOC is 130%, and the cut-off voltage of charging is 1.5V. SOC refers to the amount of charge, and normal battery SOC is generally 100% to be considered full of charge, so in order to explore the problem of 3d n@g suppressing lithium precipitation, charge is continued at soc=100% so that lithium is precipitated on the graphite surface, thereby characterizing the induced deposition effect of 3d n@g on precipitated lithium. Finally, the discharge is carried out again, the SOC is still 130%, and lithium is deposited on the graphite surface.
(2) Lithium intercalation and deintercalation: constant current charge and discharge is carried out for 10 circles, the current is 1C (1 C=340 mAh/g), the state of charge SOC is 130%, the SOC is 130% after the last discharge, then lithium is extracted at the current of 0.1C, and the cut-off voltage is 1.5V.
SEM images of deposited lithium and deintercalated lithium of the graphite anode under 1C condition are shown in fig. 8 and 9, respectively. It can be seen that the lithium ions generate uneven precipitation at the graphite negative electrode, resulting in the generation of an undensified lithium metal layer at the graphite negative electrode, and even lithium dendrites. After the lithium ions are deintercalated, a lithium deposition layer on the surface of the graphite cathode is still uneven, and a lithium dendrite structure exists. The presence of lithium dendrites affects the capacity and service life of the battery.
Study on the long cycle performance of graphite negative electrode
The graphite anodes in the first and comparative examples were used as anodes, liNi 0.8Co0.1Mn0.1O2 (NCM 811) anodes were used as anodes, the surface loads of the anode and the cathode sheets were uniform by 2.8 mAh/cm 2, and PE separators were used as separators. The electrolyte adopts 1M LiPF 6, DEC: DMC: EC=1:1:1 Vol% 1% VC, and the liquid injection amount is 3g/Ah.
At the room temperature of 25 ℃, the testing multiplying power is 2 ℃, the constant current charge and discharge are carried out, and the voltage range is 4.3V-2.8V.
The long cycle performance graphs of the soft pack batteries prepared in example one and comparative examples at 2C constant current charge and discharge are shown in fig. 10. It can be seen that the capacity retention after 1000 charge and discharge cycles was 85.50% for example one, while the capacity retention after 1000 charge and discharge cycles was only 47.56% for comparative example under the condition of 2C. From this, it can be seen that: the high-crystallinity carbon nitride coating layer is coated on the surface of the graphite negative electrode, so that the capacity retention rate of 1000 cycles of the graphite NCM811 soft-package battery can be improved by 37.94%, and the service life of the soft-package battery is greatly prolonged.
Therefore, the high-crystallinity carbon nitride coated graphite negative electrode, the preparation method and the application thereof can solve the problems of short service life and low capacity of the traditional graphite negative electrode battery.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting it, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that: the technical scheme of the invention can be modified or replaced by the same, and the modified technical scheme cannot deviate from the spirit and scope of the technical scheme of the invention.
Claims (3)
1. The graphite cathode coated with high crystallinity carbon nitride is characterized in that: the graphite negative electrode material comprises coated graphite, a binder, a conductive agent and an organic solvent, wherein the coated graphite is a uniform high-crystallinity polymerized carbon nitride layer coated on the surface of the graphite;
The current collector is copper, and the organic solvent is anhydrous N-methylpyrrolidone (NMP);
the binder is polyvinylidene fluoride PVDF, and the mass of the binder is 10% of the mass of the coated graphite;
the conductive agent is conductive carbon black Super P, and the mass of the conductive agent is 10% of the mass of the coated graphite; the preparation method of the high-crystallinity carbon nitride coated graphite cathode comprises the following steps:
s1, dissolving PVDF in anhydrous N-methylpyrrolidone NMP to obtain clear colloid liquid;
S2, uniformly dispersing the conductive agent and the coated graphite in colloid liquid, and adding anhydrous N-methyl pyrrolidone (NMP) to adjust the viscosity of the mixed liquid to 4000-8000 cps so as to obtain graphite negative electrode slurry;
s3, uniformly coating the graphite negative electrode slurry on the surface of a current collector, drying and rolling to obtain a graphite negative electrode;
In the step S2, the preparation method of the coated graphite comprises the following steps:
s21, adding a precursor material into an N-methylpyrrolidone (NMP) solvent, and uniformly mixing by using a refiner to obtain a solution;
S22, pouring the solution into a ball milling tank, and adding graphite into the ball milling tank for ball milling to obtain ball grinding materials;
s23, placing the ball-milling materials into an oven for drying, and sieving the ball-milling materials; placing the sieved powder into a tubular furnace for sintering under the protection of argon, wherein the sintering temperature is 500 ℃, and the sintering time is 1h, so as to obtain coated graphite;
In the step S21, the precursor material is dicyandiamide, and the concentration of the precursor material is 0.1mg/mL;
In the step S22, the concentration of graphite is 1g/mL.
2. The high crystallinity carbon nitride coated graphite anode of claim 1, wherein: in the step S3, the compacted density of the graphite negative electrode plate is 1.4g/cm 3-1.6g/cm3.
3. A high crystallinity carbon nitride coated graphite anode as described in claim 1 for use in a soft pack battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410696060.5A CN118263402B (en) | 2024-05-31 | 2024-05-31 | High-crystallinity carbon nitride coated graphite negative electrode and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410696060.5A CN118263402B (en) | 2024-05-31 | 2024-05-31 | High-crystallinity carbon nitride coated graphite negative electrode and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN118263402A CN118263402A (en) | 2024-06-28 |
| CN118263402B true CN118263402B (en) | 2024-09-03 |
Family
ID=91609292
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410696060.5A Active CN118263402B (en) | 2024-05-31 | 2024-05-31 | High-crystallinity carbon nitride coated graphite negative electrode and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118263402B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115347171A (en) * | 2022-08-29 | 2022-11-15 | 贝特瑞新材料集团股份有限公司 | Graphite negative electrode composite material, preparation method thereof and lithium ion battery |
| CN117712366A (en) * | 2024-02-05 | 2024-03-15 | 济南中瑞泰新材料科技有限公司 | Preparation method of coated electrode material, coated electrode material and lithium ion battery |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB201311742D0 (en) * | 2013-07-01 | 2013-08-14 | Ucl Business Plc | Electrode for use in a lithium-ion electrochemical cell |
| CN103928691B (en) * | 2014-04-10 | 2016-07-06 | 哈尔滨工业大学 | DMFC platinum based catalyst carrier and preparation method thereof |
| CN105789588A (en) * | 2016-04-06 | 2016-07-20 | 苏州思创源博电子科技有限公司 | Preparation method of multilayer structure battery cathode material containing C3N4 composite material |
| CN106328242B (en) * | 2016-08-24 | 2018-09-18 | 广州倬粤动力新能源有限公司 | It is a kind of to nitrogenize carbon-coated superconduction Graphene electrodes material and preparation method thereof |
| CN109286009B (en) * | 2018-09-25 | 2021-06-08 | 陕西科技大学 | Preparation method of nano-sheet self-assembled three-dimensional nano-flower tin sulfide/graphitized carbon nitride lithium ion battery cathode material |
| CN109817942A (en) * | 2019-02-19 | 2019-05-28 | 电子科技大学 | A method of dendritic growth when inhibiting lithium metal as battery cathode |
| KR102345758B1 (en) * | 2020-06-24 | 2021-12-31 | 한국과학기술원 | Palladium single-atom catalyst supported on C@C3N4 for electrochemical reactions and method for preparing the same |
| US20220013765A1 (en) * | 2020-07-10 | 2022-01-13 | New York University | Graphitic carbon nitride materials and methods of making and use thereof |
| CN112054175A (en) * | 2020-09-09 | 2020-12-08 | 天津工业大学 | Preparation method of graphite-phase nitrogen carbide/graphite cathode composite material with bean pod structure |
| CN114188511B (en) * | 2020-09-14 | 2024-02-27 | 湖南中科星城石墨有限公司 | Nitrogen-doped carbon-coated graphite composite material and preparation method and application thereof |
| CN112186153B (en) * | 2020-09-23 | 2022-05-20 | 长沙矿冶研究院有限责任公司 | Lithium cathode with interface nanosheet protective layer and preparation method thereof |
| CN114497546A (en) * | 2021-12-28 | 2022-05-13 | 贝特瑞新材料集团股份有限公司 | Graphite negative electrode material, preparation method thereof and lithium ion battery |
| KR20230142276A (en) * | 2022-04-01 | 2023-10-11 | 한국화학연구원 | Current collector including a coating layer coated with a carbon-based material, manufacturing method thereof, and a lithium secondary battery comprising the same |
| CN117563554A (en) * | 2023-11-16 | 2024-02-20 | 黑龙江省科学院高技术研究院 | Preparation method and application of graphite-phase carbon nitride/expanded graphite composite material |
| CN117594770A (en) * | 2023-11-30 | 2024-02-23 | 北京航空航天大学 | Three-dimensional porous carbon-carbon nitride heterostructure material, preparation method and application thereof, negative plate and application thereof |
-
2024
- 2024-05-31 CN CN202410696060.5A patent/CN118263402B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115347171A (en) * | 2022-08-29 | 2022-11-15 | 贝特瑞新材料集团股份有限公司 | Graphite negative electrode composite material, preparation method thereof and lithium ion battery |
| CN117712366A (en) * | 2024-02-05 | 2024-03-15 | 济南中瑞泰新材料科技有限公司 | Preparation method of coated electrode material, coated electrode material and lithium ion battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN118263402A (en) | 2024-06-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109845005B (en) | Positive electrode active material pre-dispersion composition, positive electrode for secondary battery, and lithium secondary battery comprising same | |
| CN111480251B (en) | Negative electrode for lithium secondary battery, method for producing same, and lithium secondary battery comprising same | |
| US9123955B2 (en) | Negative active material, lithium battery including the material, and method for manufacturing the material | |
| US20220093964A1 (en) | Anode active material for lithium secondary battery, manufacturing method thereof, and lithium secondary battery including the same | |
| US10074855B2 (en) | Electrode for lithium secondary battery and lithium secondary battery comprising the same | |
| US11799070B2 (en) | Negative electrode active material for lithium secondary battery, method of preparing the same, and negative electrode for lithium secondary battery and lithium secondary battery including the same | |
| KR101211327B1 (en) | Anode active material for secondary battery and method for preparing the same | |
| CN115020678B (en) | Positive electrode active material, electrochemical device, and electronic device | |
| CN113394370B (en) | Electrode plate and battery containing same | |
| KR20180075180A (en) | Electrode for secondary battery, method for preparing the same, and lithium secondary battery comprising the same | |
| JPWO2012144177A1 (en) | Negative electrode for lithium ion secondary battery and lithium ion secondary battery using the negative electrode | |
| CN111557056A (en) | Three-dimensional structure electrode and electrochemical device including the same | |
| JP2022548846A (en) | Cathode material for secondary battery and lithium secondary battery containing the same | |
| US20220131157A1 (en) | Negative Electrode and Lithium Secondary Battery Including Same | |
| US20230073433A1 (en) | Positive Electrode Material for Lithium Secondary Battery, and Positive Electrode and Lithium Secondary Battery Which Include the Same | |
| KR20210006869A (en) | Method for preparing positive electrode active material for secondary battery, positive electrode active material manufactured through the method and lithium secondary battery comprising the same | |
| CN113950759A (en) | Negative electrode, method for producing same, and secondary battery comprising same | |
| US20240266525A1 (en) | Positive Electrode Optimized for Improving High-Temperature Life Characteristics and Secondary Battery Comprising the Same | |
| JP2012089464A (en) | Nonaqueous electrolyte secondary battery and method for manufacturing nonaqueous electrolyte secondary battery | |
| CN113066988B (en) | Negative pole piece and preparation method and application thereof | |
| CN118263402B (en) | High-crystallinity carbon nitride coated graphite negative electrode and preparation method and application thereof | |
| CN113784916B (en) | Method for preparing negative electrode active material | |
| JP2012059721A (en) | Nonaqueous secondary battery | |
| JP2022102228A (en) | Negative electrode for secondary battery, slurry for negative electrode, and manufacturing method of negative electrode | |
| CN118270765B (en) | Preparation method of carbon material graphite negative electrode additive, graphite negative electrode and application |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |