CN115948820A - Carbon material, preparation method thereof, conductive agent and lithium ion battery - Google Patents
Carbon material, preparation method thereof, conductive agent and lithium ion battery Download PDFInfo
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Abstract
The invention relates to the technical field of lithium ion batteries, in particular to a carbon material and a preparation method thereof, a conductive agent and a lithium ion battery. The carbon material of the present invention includes carbon fibers and hollow carbon spheres attached to the carbon fibers. A method for producing a carbon material, comprising the steps of: performing electrostatic spinning on the mixture of the spinning solution and the hollow carbon spheres, and carbonizing to obtain the carbon material; the spinning solution comprises at least one of polyacrylonitrile, polyamide, polyvinyl alcohol and polyurethane. The carbon material disclosed by the invention has the advantages of conductivity, excellent electrolyte storage capacity and high infiltration rate; on the basis of not influencing the energy density of the battery, the conductivity of the electrode, the infiltration rate of electrolyte in the porous electrode and the liquid retention capacity of the electrode are improved, so that the cycling stability of the battery is improved.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a carbon material and a preparation method thereof, a conductive agent and a lithium ion battery.
Background
The infiltration rate of the electrolyte and the liquid retention capacity of the electrolyte are critical to the cycle performance of the battery. Firstly, the electrolyte impregnation of the battery core in the preparation process is uneven due to poor electrolyte impregnation capability, which affects the uniform diffusion of lithium ions in the porous electrode, and the electrolyte impregnation is uneven due to low electrolyte impregnation rate, so that the local deterioration of the pole piece is accelerated, and the cycle performance is rapidly attenuated. Secondly, along with the problems of material volume deformation, SEI film thickening and the like in the battery core circulation process, the pole piece can generate irreversible expansion and is limited in a limited expansion space, the pole piece stress can be increased along with the increase of the circulation times, electrolyte in the pole piece is easy to extrude, and then the ion transmission impedance is increased, and the circulation is quickly attenuated. Therefore, the improvement of the infiltration rate and the liquid retention capacity of the electrode has great significance for improving the cycling stability of the cell.
At present, a method for improving the liquid retention capacity of an electrode is to add a polymer liquid retention additive, and absorb more electrolyte by utilizing the high swelling property of the polymer liquid retention additive so as to slow down the cycle decay. However, polymeric liquid retention additives not only do not provide capacity, but also are non-conductive, reducing the energy density of the battery as a whole and increasing the impedance of the electrodes. In addition, when the swelling force reaches a certain value, the electrolyte adsorbed in the flexible polymer liquid retention additive may be squeezed out, and the purpose of liquid retention may not be achieved.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The first objective of the present invention is to provide a carbon material having ordered surface pore and cavity structures, and having conductive properties, excellent electrolyte storage capacity, and high wetting rate.
A second object of the present invention is to provide a method for producing the carbon material as described above.
The third objective of the present invention is to provide a conductive agent, which is beneficial to improve the conductivity of the electrode, the wetting rate of the electrolyte in the porous electrode, and the liquid retention capability of the electrode on the basis of not affecting the energy density of the battery, thereby improving the cycling stability of the battery.
A fourth object of the present invention is to provide a lithium ion battery having excellent cycle stability.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
the invention provides a carbon material, which comprises carbon fibers and hollow carbon spheres attached to the carbon fibers.
Further, the diameter of the carbon fiber is 500nm to 10 μm.
Preferably, the aspect ratio of the carbon fiber is 10 to 200:1.
further, the diameter of the hollow carbon sphere is 20 nm-5 μm.
Further, the mass ratio of the carbon fibers to the hollow carbon spheres is 0.05-5: 1.
the invention also provides a preparation method of the carbon material, which comprises the following steps: performing electrostatic spinning on the mixture of the spinning solution and the hollow carbon spheres, and carbonizing to obtain the carbon material;
the spinning solution comprises at least one of polyacrylonitrile, polyamide, polyvinyl alcohol and polyurethane.
Further, the mass ratio of the hollow carbon spheres to the spinning solution is 0.05-1.5: 1.
preferably, the temperature of the carbonization is 600 to 1200 ℃.
The invention also provides a conductive agent comprising the carbon material or the carbon material prepared by the preparation method of the carbon material.
Further, in the conductive agent, the mass percentage of the fibrous carbon material is 10% to 100%.
Further, the conductive agent further includes at least one of conductive carbon black, carbon nanotubes, graphite, superconducting carbon, acetylene black, ketjen black, carbon dots, and graphene.
The invention also provides a lithium ion battery which comprises the conductive agent.
Compared with the prior art, the invention has the beneficial effects that:
the fibrous carbon material provided by the invention comprises carbon fibers and hollow carbon spheres attached to the carbon fibers, so that the fibrous carbon material has ordered surface pore canals and cavity structures, has conductivity, excellent electrolyte storage capacity and high infiltration rate, and is used as a conductive agent, thereby being beneficial to improving the performance of an electrode and further improving the performance of a battery.
The conductive agent containing the carbon material of the present invention has a dot-line transmission mode, exhibits higher electron conductance than a zero-dimensional conductive agent, and has conductivity comparable to that of a carbon nanotube. The hollow carbon spheres in the carbon material can provide sufficient space for electrolyte storage, so that the carbon material has excellent electrolyte storage capacity. The electrolyte has higher infiltration rate in the porous electrode added with the carbon material, and the rapid infiltration of the electrolyte is ensured.
The conductive agent can improve the liquid retention capacity under the condition of not influencing the energy density and the power density of a battery, thereby improving the circulation stability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic view of preparation of hollow carbon spheres of example 1 of the present invention.
FIG. 2 is a schematic diagram of the production of a carbon material of example 1 of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present 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. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The carbon material, the preparation method thereof, the conductive agent and the lithium ion battery according to the embodiment of the present invention will be specifically described below.
In some embodiments of the present invention, a carbon material is provided that includes carbon fibers and hollow carbon spheres attached to the carbon fibers.
The carbon material is of a fibrous structure and comprises carbon fibers and hollow carbon spheres attached to the carbon fibers, so that the carbon material has ordered surface pore channels and cavity structures. The carbon material has a point-line electron transmission mode, and shows higher electron conductance compared with a point-point electron transmission mode of a zero-dimensional conductive agent, such as carbon black, super P, acetylene black and the like; the diffusion rate of the electrolyte in the porous electrode structure added with the one-dimensional carbon material with high length-diameter ratio is higher than that of the electrolyte added with the zero-dimensional conductive agent; the cavity structure of the hollow carbon spheres of the carbon material provides sufficient space for storing the electrolyte, and improves the liquid retention capacity of the electrode, so that the extrusion of the electrolyte caused by the expansion of the electrode in the battery circulation process, the impedance increase and the capacity rapid attenuation caused by the loss of the liquid are reduced; the electrolyte infiltration rate and the electrolyte retention capacity of the pole piece added with the carbon material are improved, so that the cycling stability of the battery is improved.
In some embodiments of the invention, the carbon fibers have a diameter of 500nm to 10 μm; typically, but not by way of limitation, the carbon fibers have a diameter of, for example, 500nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, and the like.
In some embodiments of the invention, the carbon fiber has an aspect ratio of 10 to 200:1; typically, but not by way of limitation, carbon fibers have an aspect ratio of 10: 1. 50: 1. 100, and (2) a step of: 1. 150:1 or 200:1, etc.
In some embodiments of the invention, the hollow carbon spheres have a diameter of 20nm to 5 μm; typically, but not by way of limitation, the hollow carbon spheres have a diameter of, for example, 20nm, 200nm, 600nm, 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm, and the like. Preferably, the hollow carbon spheres have a diameter of 200nm to 500nm.
In some embodiments of the present invention, the mass ratio of the carbon fibers and the hollow carbon spheres is 0.05 to 5:1; typically, but not limitatively, the mass ratio of carbon fibers and hollow carbon spheres is, for example, 0.05: 1. 0.1: 1. 0.5:1. 1: 1. 2: 1. 3: 1. 4:1 or 5:1, etc. Preferably, the mass ratio of the carbon fibers to the hollow carbon spheres is 0.1 to 0.5:1.
in some embodiments of the present invention, there is also provided a method for preparing the above carbon material, comprising the steps of:
performing electrostatic spinning on the mixture of the spinning solution and the hollow carbon spheres, and carbonizing to obtain a carbon material;
the spinning solution comprises at least one of polyacrylonitrile, polyamide, polyvinyl alcohol and polyurethane.
In some embodiments of the invention, the solvent in the dope comprises at least one of methanol, ethanol, isopropanol, diethyl ether, propylene oxide, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, dichloromethane, acetone, methyl butanone, methyl isobutyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, acetonitrile, pyridine, benzene, and N, N-dimethylformamide.
The spinning solution and the hollow carbon spheres are spun by pulse voltage to obtain the fibrous composite material with adjustable diameter, adjustable length-diameter ratio and adjustable liquid retention space, and then the fibrous composite material is carbonized to obtain the fibrous carbon material.
In some embodiments of the present invention, the mass ratio of the hollow carbon spheres to the spinning solution is 0.05 to 1.5:1; typically, but not by way of limitation, the mass ratio of hollow carbon spheres to spinning solution is, for example, 0.05: 1. 0.1: 1. 0.5:1. 1:1 or 1.5:1, etc.
In some embodiments of the invention, the pulse voltage frequency for electrospinning is from 0.1 to 10HZ.
In some embodiments of the invention, the temperature of carbonization is 600 to 1200 ℃; typically, but not by way of limitation, the temperature of carbonization is, for example, 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, or the like.
In some embodiments of the present invention, the method of preparing the hollow carbon spheres comprises a hard template method; preferably, the preparation method of the hollow carbon sphere comprises: polymerizing phenolic resin on the surface of the silicon dioxide ball in situ, and then sequentially carrying out carbonization, hydrofluoric acid etching and cleaning.
In some embodiments of the present invention, there is also provided a conductive agent comprising the above carbon material or the carbon material produced by the above method for producing a carbon material.
The conductive agent provided by the invention can improve the conductivity of the electrode, can improve the wetting rate of electrolyte in the porous electrode and the liquid retention capacity of the battery, endows the conductive agent with the liquid retention function, improves the liquid retention capacity of the battery under the condition of not influencing the energy density and power density of a conductive cell, and further improves the circulation stability.
In some embodiments of the invention, the conductive agent comprises 10 to 100% by weight of the carbon material; typically, but not limited to, for example, the mass percent of carbon material in the conductive agent is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%, etc.
In some embodiments of the present invention, the conductive agent further comprises at least one of conductive carbon black, carbon nanotubes, graphite, superconducting carbon, acetylene black, ketjen black, carbon dots, and graphene.
In some embodiments of the invention, the conductive agent comprises a positive membrane conductive agent and a negative membrane conductive agent.
In some embodiments of the invention, the positive membrane conductive agent comprises a carbon material, and conductive carbon black and/or carbon nanotubes; preferably, the positive electrode membrane conductive agent includes a carbon material, conductive carbon black, and carbon nanotubes.
In some embodiments of the invention, the negative membrane conductive agent comprises a carbon material and at least one of graphite, superconducting carbon, acetylene black, conductive carbon black, ketjen black, carbon dots, carbon nanotubes, and graphene; preferably, the negative electrode membrane conductive agent includes a carbon material, conductive carbon black, and carbon nanotubes.
Also provided in some embodiments of the present invention is a lithium ion battery comprising the above-described conductive agent.
In some embodiments of the present invention, a lithium ion battery comprises a positive electrode plate, a negative electrode plate, a separator, and an electrolyte;
the positive pole piece comprises a positive active material, a positive diaphragm conductive agent and a binder;
the negative pole piece comprises a negative active material, a negative diaphragm conductive agent and a binder.
In some embodiments of the present invention, the positive active material includes LiCoO 2 、LiFePO 4 、LiMn 2 O 4 、LiMn 1- y M y PO 4 、LiMn 1-y M y O 4 And LiNi x Co y Mn z M 1-x-y-z O 2 At least one of; wherein, M is any one of Fe, co, ni, mn, mg, cu, zn, al, sn, B, ga, cr, sr, V and Ti, y is more than or equal to 0 and less than or equal to 1,0 and less than or equal to 1,0 and less than or equal to z and less than or equal to 1, and x + y + z is less than or equal to 1.
In some embodiments of the invention, the binder in the positive electrode sheet comprises polyvinylidene fluoride (PVDF).
In some embodiments of the present invention, the kind of the current collector of the positive electrode sheet is not particularly limited, and may be selected according to actual requirements, for example, the current collector of the positive electrode sheet is an aluminum foil, a nickel foil, or a polymer conductive film, and preferably, the current collector of the positive electrode sheet is a 12 μm aluminum foil.
In some embodiments of the present invention, the negative active material includes at least one of artificial graphite, natural graphite, soft carbon, and a Si/C composite material.
In some embodiments of the present invention, the binder of the negative electrode tab includes at least one of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin (water-based resin), and carboxymethyl cellulose (CMC).
In some embodiments of the invention, the current collector of the negative electrode tab comprises a metal foil, such as copper foil. Preferably, the thickness of the current collector of the negative electrode sheet is 4 to 12 μm, more preferably 4.5 to 8 μm.
In some embodiments of the invention, the electrolyte comprises an organic solvent, a lithium salt, and a film-forming additive;
the organic solvent comprises a first solvent and a second solvent; the first solvent comprises a linear carboxylic acid ester and/or ethylene carbonate; the second solvent comprises at least one of ethyl methyl carbonate, diethyl carbonate and dimethyl carbonate propylene carbonate;
the film forming additive comprises at least one of fluoroethylene carbonate, vinylene carbonate, 1,3-propane sultone, succinonitrile, adiponitrile, lithium bis (oxalato) borate and lithium bis (oxalato) borate;
the lithium salt comprises LiPF 6 、LiBF 4 、LiTFSI、LiClO 4 At least one of LiODFB and LiBOB.
In some embodiments of the present invention, a barrier film includes a base film and a coating layer attached to a surface of the base film; the base film comprises at least one of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP) and aramid fiber, and the coating comprises Al 2 O 3 And PVDF.
In some embodiments of the present invention, a method for preparing a lithium ion battery includes the following steps of stacking a positive electrode plate, an isolation film, and a negative electrode plate in sequence, so that the isolation film is positioned between the positive electrode plate and the negative electrode plate to perform an isolation function, thereby obtaining a battery cell; and (3) placing the battery core in a packaging shell, injecting electrolyte and sealing to obtain the lithium ion battery.
On the basis of the same surface density and the same compacted density, the pole piece adopting the conductive agent disclosed by the invention has higher liquid absorption rate and higher liquid retention rate, and the battery has better cycling stability.
Example 1
The preparation method of the lithium ion battery provided by the embodiment includes the following steps:
stacking the positive pole piece, the isolating membrane and the negative pole piece in sequence, and enabling the isolating membrane to be positioned between the positive pole piece and the negative pole piece to obtain a battery cell; and (4) placing the battery core in a packaging shell, injecting electrolyte and sealing to obtain the lithium ion battery. The lithium ion battery capacity is designed to be 126Ah.
Wherein the electrolyte consists of an organic solvent, lithium salt and a film-forming additive; wherein the organic solvent consists of 25wt% EC, 35wt% DEC, 30wt% EMC, 5wt% DMC and 5wt% PC; the lithium salt being LiPF 6 The concentration of lithium salt in the electrolyte is 1.05M; the film-forming additive is composed of VC and LiPO 2 F 2 And MMDS; VC and LiPO in electrolyte 2 F 2 And the concentration of MMDS was 1wt%, 0.5wt%, and 0.5wt% in this order.
The diaphragm is a PE basal membrane (9 mu m), a PVDF coating (1 mu m) and A which are contacted in sequence 2 O 3 Ceramic coating (1 μm).
The preparation method of the positive electrode plate (1 #) provided by the embodiment includes the following steps:
reacting LiNi 8 Co 1 Mn 1 O 2 The positive electrode sheet conductive agent and the PVDF are mixed evenly to obtain slurry, then the prepared slurry is coated on two sides of an aluminum foil with the thickness of 12 mu m, and the positive electrode sheet (No. 1) is obtained after baking, rolling and cutting. LiNi 8 Co 1 Mn 1 O 2 And the mass ratio of the positive electrode diaphragm conductive agent to the PVDF is 95.5:2:2.5; the positive electrode diaphragm conductive agent is prepared from SP, a carbon nano tube and a carbon material according to the mass ratio of 6:3:1 are mixed to obtain the product.
The preparation method of the negative electrode plate (2 #) provided by the embodiment includes the following steps:
and uniformly mixing graphite, the negative electrode diaphragm conductive agent, CMC and SBR to obtain slurry, coating the prepared slurry on two sides of a copper foil, baking, rolling and cutting into pieces to obtain the negative electrode piece # (2 #). The mass ratio of the graphite to the negative membrane conductive agent to the CMC to the SBR is 96.5:1.5:1:1; the negative electrode diaphragm conductive agent is prepared from SP, a carbon nano tube and a carbon material according to the mass ratio of 6:3:1 are mixed to obtain the product.
A method for producing a carbon material, comprising the steps of:
(1) Uniformly stirring 7mL of tetrapropoxysilane, 7mL of tetraethyl silicate, 280mL of ethanol and 40mL of ultrapure water to obtain a mixed solution; and then adding 12mL of ammonia water into the mixed solution, magnetically stirring for 30min, adding 1.6g of resorcinol and 2.25mL of formaldehyde, continuously stirring for 24h to obtain solid powder, washing with ultrapure water for 5 times, drying at 80 ℃, fully grinding, sealing and storing for later use.
(2) And (2) placing the porcelain boat filled with the solid powder in the step (1) in a tube furnace protected by nitrogen atmosphere, ventilating for 1h, exhausting air, heating to 800 ℃ at the speed of 5 ℃/min, preserving heat for 3h, cooling to room temperature to obtain solid powder, and grinding for later use.
(3) And (3) placing the solid powder obtained in the step (2) in a 5wt% hydrofluoric acid solution, standing for 24h, washing with ultrapure water and ethanol for 3 times respectively, drying at 80 ℃, and grinding to obtain the hollow carbon spheres.
(4) Dispersing hollow carbon spheres into a DMF solution, and uniformly dispersing by ultrasonic; 0.7371g polyacrylonitrile and hollow carbon spheres are mixed according to the mass ratio of 2:1 into DMF dispersion liquid of hollow carbon spheres, and magnetically stirring for 8-12 h to prepare mixed solution; and (3) adjusting parameters of the electrostatic spinning machine (the rotating speed of a roller is 200rpm, the voltage is 10KV, the moving distance of a spray head is 6cm, the spraying speed is 9uL/min, and the pulse frequency is 20 HZ), and then performing pulse spinning to obtain the carbon material.
Example 2
The method for preparing a lithium ion battery provided in this embodiment refers to embodiment 1, and is different in that in the method for preparing a positive electrode sheet (3 #) in this embodiment, the mass ratio of SP to carbon nanotubes to a carbon material is 6:1:3. in the preparation method of the negative electrode plate (4 #) of the embodiment, the mass ratio of the SP to the carbon nanotube to the carbon material is 6:1:3.
example 3
The lithium ion battery provided in this embodiment is prepared by referring to example 1, except that the positive electrode tab is the positive electrode tab (1 #) prepared in example 1, and the negative electrode tab is the negative electrode tab (4 #) prepared in example 2.
Example 4
The preparation method of the lithium ion battery provided in this embodiment refers to embodiment 1, except that the positive electrode plate is the positive electrode plate (# 3) prepared in embodiment 2, and the negative electrode plate is the negative electrode plate (# 2) prepared in embodiment 1.
Example 5
The preparation method of the lithium ion battery provided in this embodiment is as in example 1, except that in the preparation method of the carbon material, the mass ratio of polyacrylonitrile to hollow carbon spheres is 5:1.
example 6
The preparation method of the lithium ion battery provided in this embodiment refers to embodiment 1, and the difference is that in the preparation method of the carbon material, the mass ratio of polyacrylonitrile to hollow carbon spheres is 9:1.
comparative example 1
The preparation method of the lithium ion battery provided by the comparative example refers to example 1, and is different in that in the preparation method of the positive electrode plate (5 #), the conductive agent of the positive electrode membrane is prepared from SP and carbon nanotubes according to a mass ratio of 7:3 mixing to obtain; in the preparation method of the negative pole piece (6 #), the conductive agent of the positive pole membrane is prepared from SP and carbon nano tubes according to the mass ratio of 7:3 mixing to obtain the product.
Test example 1
The positive/negative electrode sheets (1 # -6 #) in examples 1-2 and comparative example 1 were used as experimental subjects, and the liquid absorption rate and liquid retention amount of the positive/negative electrode sheets were measured, and the test results are shown in table 1.
TABLE 1
| Positive/negative pole piece | Pole piece resistivity (omega cm) | Imbibition rate (mL/min) | Liquid retention amount/g |
| 1# | 15.1 | 3.6 | 0.9 |
| 2# | 10.1 | 4.5 | 0.85 |
| 3# | 15.3 | 4.1 | 1.0 |
| 4# | 9.9 | 5.2 | 0.95 |
| 5# | 15.2 | 3.2 | 0.75 |
| 6# | 10.0 | 4.1 | 0.7 |
As can be seen from Table 1, the sheet resistivity of the comparative examples and comparative examples, the sheet resistivity of the carbon material of the present invention substituted CNT and changed significantly, indicating that the conductivity of the carbon material of the present invention is equivalent to that of CNT; the liquid absorption rate and the liquid retention capacity of the pole piece of the embodiment are superior to those of the comparative example, which shows that the carbon material of the invention has the function of increasing the liquid absorption rate and the liquid retention capacity.
Test example 2
The lithium ion batteries prepared in examples 1 to 4 and comparative example 1 were subjected to an expansive force cycle test, and DCIR and capacity retention rate were analyzed for 500 cycles of the batteries under the test conditions (expansive force jig, 1C/1C rate charge and discharge, aerogel pad, and 3% expansion gap reserved), and the results are shown in table 2.
TABLE 2
| DCIR(mΩ) | Capacity retention (%) | |
| Example 1 | 0.930 | 97.9 |
| Example 2 | 0.930 | 98.7 |
| Example 3 | 0.927 | 98.5 |
| Example 4 | 0.928 | 98.1 |
| Comparative example 1 | 0.929 | 97.1 |
As can be seen from table 2, the DCIR of the lithium ion batteries prepared in examples 1 to 4 and comparative example 1 was substantially consistent after 500 weeks of cycling, indicating that the carbon fiber of the present invention has excellent conductivity, and the addition thereof does not affect the internal resistance of the cell; compared with comparative example 1, the capacity retention rates of examples 1 to 4 were improved to different degrees, demonstrating the effectiveness and rationality of the carbon fiber (Csf) of the present invention for cycle improvement; the higher capacity retention ratio of example 2 or 3 compared to example 1 or 4 indicates that increasing the carbon material content of the negative electrode is more beneficial to improving the battery cycle stability.
In conclusion, the carbon material disclosed by the invention not only has excellent conductivity, but also has the effects of improving the liquid absorption rate of the pole piece, the liquid retention energy and the cell circulation energy.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A carbon material comprising carbon fibers and hollow carbon spheres attached to the carbon fibers.
2. The carbon material according to claim 1, wherein the carbon fiber has a diameter of 500nm to 10 μm;
preferably, the aspect ratio of the carbon fiber is 10 to 200:1.
3. the carbon material according to claim 1, wherein the diameter of the hollow carbon sphere is 20nm to 5 μm.
4. The carbon material according to claim 1, wherein the mass ratio of the carbon fibers to the hollow carbon spheres is 0.05 to 5:1.
5. the method for producing a carbon material as claimed in any one of claims 1 to 4, comprising the steps of: performing electrostatic spinning on the mixture of the spinning solution and the hollow carbon spheres, and carbonizing to obtain the carbon material;
the spinning solution comprises at least one of polyacrylonitrile, polyamide, polyvinyl alcohol and polyurethane.
6. The method for producing a carbon material according to claim 5, wherein the mass ratio of the hollow carbon spheres to the spinning solution is 0.05 to 1.5:1;
preferably, the temperature of the carbonization is 600 to 1200 ℃.
7. A conductive agent comprising the carbon material according to any one of claims 1 to 4 or the carbon material produced by the method for producing a carbon material according to claim 5 or 6.
8. The conductive agent according to claim 7, wherein the mass percentage of the carbon material in the conductive agent is 10% to 100%.
9. The conductive agent as claimed in claim 7, wherein the conductive agent further comprises at least one of conductive carbon black, carbon nanotubes, graphite, superconducting carbon, acetylene black, ketjen black, carbon dots, and graphene.
10. A lithium ion battery comprising the lithium ion battery according to any one of claims 7 to 9
A conductive agent.
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| CN117117179A (en) * | 2023-10-25 | 2023-11-24 | 浙江帕瓦新能源股份有限公司 | Carbon negative electrode material, preparation method thereof and sodium ion battery |
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